Infraclass Teleostei Müller, 1845 sensu Arratia (1999)
Order Gobiiformes Günther, 1880 sensu Betancur-R et al. (2017)
Suborder Gobioidei Jordan and Evermann, 1896 sensu Thacker et al. (2015)
Family Gobiidae Cuvier, 1816 sensu Nelson et al. (2016)
Genus †Katyagobius gen. nov.
Type species. †Katyagobius prikryli gen. et sp. nov. (Figs. 5a, 6a, 7a, 8a, 9a, 10a).
Other species. †Katyagobius sp. (Figs. 6b, 7b, 9b–d, 10b, c, Supplementary Data 3) from the same locality.
Etymology. The generic epithet honours the goby expert Dr. Ekaterina (= Katya) D. Vasil’eva (Zoological Museum, Moscow, Russia) for her important work on the osteology and diversity of the gobiid fishes from the Caspian Basin. Gender masculine.
LSID ZooBank. This new genus is registered under urn:lsid:zoobank.org:act:15083225-AFA5-468D-A909-17411888AE4A.
Stratigraphic range. Lower Sarmatian.
Diagnosis. †Katyagobius gen. nov. is a small gobiid fish; SL between 31 and 36.2 mm. Head moderately large (23.9–25.7% SL); body probably laterally compressed (as preserved in lateral view); body depth 17.7–18.5% SL at origin of D1; anal fin inserted one to two vertebrae behind D2; caudal peduncle moderately long (20.2–21.0% SL); caudal fin lanceolate and approximately as long as head (24.9–27.4% SL); length of abdominal part of vertebral column approx. 53% of that of caudal part. Number of vertebrae 28 (10 + 18); D1 with six relatively robust, distally filamentous spines; distance between spines V and VI is 4.5–4.7% SL; pterygiophore formula 3-22110; D2 with relatively long spine (8.4–9.9% SL) that tapers to a distal filament, and 15 segmented rays; anal fin with moderately long spine (4.8–6.3% SL) and 14 segmented rays. Pectoral fin with 10 to 13 rays. Pelvic fin length 16.1–17.1% SL; pelvic fin with relatively long spine (6.0–6.5% SL, 57–66% of adjacent ray) and five rays; end of pelvic rays distant from anal fin origin. Caudal fin with 16–17 segmented rays, nine rays in the upper lobe. Relatively dense cover of ctenoid (in type species) or cycloid scales (in †Katyagobius sp.) on body.
Otoliths—Sagitta slightly trapezoid, rounded; ventral portion of posterior margin bulged; sulcus ‘shoe-sole’ shaped, moderately inclined (α = 9.6–15.7°), with well-developed crista inferior along cauda. Lapillus rectangular-to-ovate in type species, otherwise ovate; relatively thick (LH/LT 2.5–2.7); in lateral view with straight to weakly convex ventral side, symmetrically convex dorsal side, and slightly tapering anterior tip.
Differential diagnosis. With respect to the presence of a longish lanceolate caudal fin, large numbers of rays in the D2 and anal fin, and general proportions of head and body, the extant genus Lesueurigobius Whitley, 1950 and the three other new fossil genera described here, i.e., †Pseudolesueurigobius gen. nov., †Sarmatigobius gen. nov., and †Yarigobius gen. nov. are phenotypically similar to †Katyagobius gen. nov. (see Table 1 for data on the fossils and Appendix Table for data on Lesueurigobius). With regard to the skeletal characters, the relatively robust D1 spines (Fig. 7a) and the comparatively long pelvic-fin spine (6.0–6.5% SL vs. 3.8–5.2% SL [no data for †Sarmatigobius gen. nov.]) are characteristic for †Katyagobius gen. nov. Furthermore, the sagitta and lapillus of †Katyagobius gen. nov. are each unique in shape (Figs. 9a–d, 10a–c). Seen in lateral view, the lapillus has a distinctive contour and is relatively thicker than any of the other lapilli studied here (ratio lapillus height/thickness 2.5–2.7 vs. 3.0–3.3 [no data for Pseudolesueurigobius gen. nov.]). Furthermore, †Katyagobius gen. nov. can be distinguished from both Lesueurigobius and †Pseudolesueurigobius gen. nov. by its total number of vertebrae (28 vs. 27); from both †Pseudolesueurigobius gen. nov. and †Sarmatigobius gen. nov. by the relatively longer distance between D1-spines V and VI (4.5–4.7% SL vs. 3.0–3.4% SL), a slightly longer caudal peduncle (20.2–21.0% SL vs. 18.0–18.5% SL), and a relatively shorter caudal fin (24.9–27.4% SL vs. 32.6–33.8% SL); from †Sarmatigobius gen. nov. also by the more posterior insertion of the anal fin (one to two vertebrae behind D2 vs. opposite); and from †Yarigobius gen. nov. by a smaller body depth at the origin of D1 (17.7–18.5% SL vs. 21.4–21.7% SL), slightly shorter pelvic fins (16.1–17.1% SL vs. 20.9–22.9% SL), and a D1 pterygiophore formula starting with 3–2… (vs. 3–1…).
Table 1 Morphological characters of the new gobiid fossils from Karpov Yar, Naslavcea, northern Moldova †Katyagobius prikryli gen. et sp. nov.
Figures 5a, 6a, 7a, 8a, 9a, 10a; Table 1
Type material. Holotype, PIN 5274/21a, b; 31.0 mm SL; part and counterpart in lateral view; part complete except for the posterior part of caudal peduncle and caudal fin, with left sagitta and right lapillus preserved in situ; counterpart complete except for the pectoral girdle and posterior part of head.
Type locality and age. Karpov Yar, Naslavcea, northern Moldova; lower Sarmatian.
Etymology. In honour of Dr. Tomáš Přikryl (Charles University and Czech Academy of Sciences, Prague, Czech Republic), for his excellent work on Oligocene–Miocene fish species and diversity.
LSID ZooBank. This new species is registered under urn:lsid:zoobank.org:act:E5BE05B1-EC88-4086-83B1-F020F6BDF28E.
Diagnosis. SL 31 mm; head moderately large (23.9% SL); caudal peduncle relatively long (21.0% SL); caudal fin lanceolate and slightly longer than head (27.4% SL); spine I of D1 robust and moderately long (87% of length of spine II); D2 with relatively long spine (8.4% SL) and moderately long filament; anal-fin spine moderately long (4.8% SL); pelvic-fin spine robust and relatively long (6.5% SL, 66% of adjacent ray); relatively dense cover of ctenoid flank scales with thickened posterior margins; about 32 scales in the longitudinal row. Other characters as described in the generic diagnosis.
General description. Relatively small gobiid fish of 31 mm SL (Fig. 5a). Body slender, tapering posteriorly, probably laterally compressed (as preserved in lateral view); head of moderate size (23.9% SL); D2 slightly in front of insertion of anal fin; relatively long caudal peduncle (21.0% SL); caudal fin lanceolate and slightly longer than head (27.4% SL). For further body proportions and meristic counts, see Table 1.
Neurocranium—The neurocranium is preserved in lateral view; it is relatively deep, but most of its bones are not well preserved. The eyes are relatively large (6.8% SL). The frontal bones are long and oriented obliquely to the body axis over the orbit, narrow between the orbits and broad posteriorly. The parasphenoid is a straight, thin rod with a broad posterior portion; the vomer is recognizable, but its shape is not clear. The ethmoid region is short. Whether scales are present on the head is unclear.
Jaws—The lower jaw is relatively long (10.6% SL); the mandibular joint is situated opposite to the middle of the orbit. The dentary is narrow anteriorly and becomes deeper posteriorly; it has a broad coronoid process. A slightly displaced long anguloarticular is also visible. Both the dentary and the premaxilla bear curved and straight, relatively long, slender and pointed teeth of different sizes. The upper jaw bones are badly damaged; the preserved parts of the premaxilla bear a relatively long and slender ascending process and a wide, rounded articular process; the maxilla is not preserved.
Suspensorium, opercular apparatus and hyoid arch—The suspensorium and opercular bones are poorly preserved. Five branchiostegal rays are recognizable in more or less anatomical connection with the hyoid bar (Fig. 6a); the first ray is thin, the last one expanded; the shape of the hyoid bar is not clear.
Branchial arches—Most of the bones of the branchial skeleton are not identifiable. The well preserved and large lower (= ceratobranchial 5, see Kindermann et al. 2007) and upper pharyngeal jaws (= pharyngobranchials 2–4, see Kindermann et al. 2007) bear teeth of different sizes and shapes; most teeth are long, slender and either straight or slightly curved; some teeth are conical, more robust and shorter.
Vertebral column—There are 28 vertebrae, of which 10 are abdominal. The length of the abdominal part of the vertebral column is 52.9% of the length of the caudal part. The vertebral centra are constricted in the middle, with the centrum length being longer than the centrum height (holds for both abdominal and caudal centra). Only few parapophyses are recognizable. The first caudal vertebra bears a haemal spine that is almost as long as the second haemal spine (Fig. 5a2). Ribs are not easily recognizable (mostly covered by pectoral fin), the last two pairs are relatively short; tiny epineurals are also present. The supraneurals are absent.
Pectoral girdle and fins—The posttemporal is well preserved; its processes are long and slender, the upper process is slightly longer than the lower. The cleithrum is massive, long and only slightly curved. The pectoral radials are broad, but their precise shape is not discernible. The pectoral fin is relatively long (Fig. 5a1); it contains at least 10 (perhaps 12) thin rays.
Pelvic girdle and fins—The length of the pelvic fins is 16.1% SL; each fin contains five soft rays and a robust, relatively long spine (6.5% SL, 66% of adjacent ray), which is longer than the anal-fin spine. The pelvic-fin rays terminate distant from the origin of the anal fin (Fig. 5a2).
Dorsal fins—The D1 consists of six relatively robust spines (Fig. 7a); spines I–V taper posteriorly into short filaments; spine II longest (12.5% SL); spine I slightly shorter (86.6% of spine II); spines III and IV long (93.8 and 91.5% of spine II); spines V and VI decreasing in length (71.4% and 45.9% of spine II, respectively); distance between spines V and VI relatively large (twice the distance between spines IV and V). The pterygiophore formula cannot be unambiguously defined, but is most probably 3-22110. The D2 inserts opposite to the origin of the first caudal vertebra (Fig. 5a2); it has a thin, curved, long spine (8.4% SL), narrowing to a filament distally; the number of segmented and branched D2 rays is 15; whether they reach the procurrent caudal-fin rays is not clear, because of the poor preservation in this region.
Anal fin—The anal fin inserts opposite to the junction between the second and third caudal vertebrae (roughly two vertebrae behind the origin of D2; Fig. 5a). It comprises a moderately long (4.8% SL), straight, thin spine and 14 segmented and branched rays; it is not clear whether their distal ends reach the caudal fin origin, owing to the poor preservation of the holotype in this region. Several anal-fin pterygiophores are visible; they are unusually short (but it is possible that only their distal parts are preserved); two pterygiophores insert before the haemal spine of the first caudal vertebra (Fig. 5a2).
Caudal endoskeleton and fin—The well-preserved caudal fin of the counterpart is lanceolate in shape (Fig. 5a1). The caudal fin is composed of 17 segmented principal rays, of which the outermost are not branched; 9 rays are found in the upper lobe. The proximal portion of the principal rays is covered by one to two vertical rows of ctenoid scales (Fig. 8a). Four and five procurrent rays are present dorsally and ventrally, respectively. The bones of the caudal endoskeleton are concealed by the dense scale cover.
Otoliths—For measurements of the sagitta and lapillus, see Table 1, for the described characters, see Figs. 9a, 10a.
Sagitta: Inner (= medial) face of sagitta flat; outer (= lateral) face convex, with large central hump covering about 2/3 of outer face; general sagitta shape slightly trapezoid, rounded; dorsal margin rounded, highest posteriorly, slightly indented in the middle; posterior margin slightly concave in the middle, ventral portion with protruding bulge; ventral margin faintly curved, with slight undulations; weak, rounded preventral protuberance; anterior margin slightly undulated, with small incision above preventral protuberance, otherwise straight; ventral line relatively broad, ending with some distance from the ostium tip and cauda end; dorsal depression shallow; sulcus of ‘shoe-sole’ shape and moderately inclined (α = 9.6–15.7°); ostium elongate, with shallow upper and lower lobes; cauda narrow and terminally rounded; crista superior weak; crista inferior well developed along cauda and posterior part of ostium.
Lapillus: In ventral view, the lapillus is rectangular-to-ovate and exhibits a relatively long, horse-shoe-shaped cranial suture and well-defined sulculus; a linea basalis is not recognizable, possibly due to the small size of the lapillus; in lateral view it has a straight to weakly convex ventral outline, a symmetrically convex dorsal side, and a slightly tapering anterior tip. The lapillus is relatively thick.
Scales—All scales are ctenoid. The flank scales are ovate, relatively large and display relatively thick posterior margins (Fig. 11a); ctenii are short; radii appear to be absent (or may have been thin and were not preserved). Scale number in longitudinal row is about 32. The predorsal scales are absent; the belly scales are similar to the flank scales, but slightly smaller. Two transverse rows of scales overlie the base of the caudal-fin rays (Fig. 8a).
†Katyagobius sp.
Figures 6b, 7b, 9b–d, 10b, c; Table 1; Supplementary Data 3.
Material. Two incomplete specimens. PIN 5274/35a, b; estimated SL based on the sagitta size is 35.9 mm; part and counterpart exhibiting the head and abdominal portion of the body in lateral view; part with left sagitta and both lapilli preserved in situ. Specimen PIN 5274/75a, b; SL 36.2 mm; part and counterpart in lateral view; part with well preserved head with both sagittae and left lapillus preserved in situ, abdominal portion of the body also relatively well preserved but caudal portion incomplete; counterpart almost complete, but poorly preserved.
Locality and age. Karpov Yar, Naslavcea, northern Moldova; lower Sarmatian.
Remarks. For body proportions and meristic counts of the two specimens, see Table 1. They have been assigned to †Katyagobius gen. nov. because they share with the type species, †K. prikryli gen. et sp. nov., the configuration of the last three D1-spines, with the distance between spines V and VI being twice the distance as between spines IV and V. Furthermore, they share with the type species the presence of a relatively long and robust pelvic fin spine, and the shape, relative thickness and contour of the lapilli (Fig. 10b, c). The two specimens differ from †K. prikryli gen. et sp. nov. because their flank scales are exclusively (PIN 5274/75) or mostly cycloid (PIN 5274/35) (vs. exclusively ctenoid in †K. prikryli gen. et sp. nov.). Their sagittae display a more rounded ventral margin and a slightly thicker dorsal margin as seen in †K. prikryli gen. et sp. nov., the latter characteristic is especially well visible in the dorsal views of the sagittae (Fig. 9b2, c2).
Differences between the two specimens include the length of the lower jaw (estimated 8.1% SL in PIN 5274/35 vs. 11.9% SL in PIN 5274/75), the predorsal distance to D1 (estimated 29.0% SL in PIN 5274/35 vs. 34.2% SL in PIN 5274/75), the predorsal distance to D2 (estimated 45.7% SL in PIN 5274/35 vs. 53.0% SL in PIN 5274/75), the number of pectoral fin rays (12 or 13 in PIN 5274/35 vs. c. 10 in PIN 5274/75) and the squamation (cycloid plus a few ctenoid scales in PIN 5274/35 vs. exclusively cycloid in PIN 5274/75). Also, the sagittae of the two specimens differ slightly from each other in the curvature of the dorsal margin (well rounded in PIN 5274/35 vs. flattened in PIN 5274/75, see Fig. 9b1 vs. c1, d1), in the curvature of the inner face (plan in PIN 5274/35 vs. slightly concave in PIN 5274/75, see Fig. 9b2 vs. c2) and also in the curvature of the outer face (moderately thickened in PIN 5274/35 vs. strongly thickened in PIN 5274/75). These differences could indicate the presence of two species, but, as each of the specimens is incomplete, we prefer to leave them in open nomenclature.
Genus †Pseudolesueurigobius gen. nov.
Type species. †Pseudolesueurigobius manfredi gen. et sp. nov. (Figs. 5b, 6d, e, 7c, 8b, 9e, 10d, 11b).
Other species. None.
Etymology. The generic name refers to the similarity of this fossil genus to the extant gobiid Lesueurigobius Whitley, 1950. Gender masculine.
LSID ZooBank. This new genus is registered under LSID urn:lsid:zoobank.org:act:78B80CDA-2630-45E6-8E12-AF21FFAB9AF8.
Stratigraphic range. Lower Sarmatian.
Diagnosis. Medium-sized gobiid fish up to 65 mm SL. Head moderately large (24.1–24.4% SL); body probably laterally compressed (being preserved in lateral view); pre-anal distance relatively long (57.6–58% SL); anal fin inserted two vertebrae behind D2; anal-fin base moderately long (24.6–25.2% SL); caudal peduncle moderately long (18.0–18.3% SL); caudal fin lanceolate and longer than head (33.4–33.8% SL); length of abdominal part of vertebral column approx. 53% of length of caudal part of vertebral column. Total number of vertebrae 27 (10 + 17); D1 with six slender, distally filamentous spines; distance between the D1-spines V and VI relatively short (3.2–3.4% SL); pterygiophore formula 3-22110; D2 with relatively long spine (7.8–8.0% SL) tapering to a distal filament and 14–16 segmented rays; anal fin with relatively short spine (3.3–4.5% SL) and 14 segmented rays. Pectoral fin with about 12 rays. Pelvic fin with moderately long spine (3.8–5.0% SL, 34% of adjacent ray) and five rays; end of pelvic rays distant from anal-fin origin. Caudal fin with 17 segmented rays, 9 rays in the upper lobe. Relatively dense cover of ctenoid scales on body.
Otoliths—Sagitta trapezoid-to-rounded in shape, with the ventral portion being distinctively wider than the dorsal part; sulcus ‘shoe-sole’-shaped, moderately inclined (α = 9.8°), with well-developed crista superior and crista inferior. Lapillus more or less ovate and tapering posteriorly; lateral margin relatively straight; medial margin strongly convex.
Differential diagnosis. With respect to the presence of a lanceolate caudal fin, high number of rays in the D2 and anal fin, and general proportions of head and body, Lesueurigobius Whitley, 1950 and the three other new fossil genera described in this study, i.e., †Katyagobius gen. nov., †Sarmatigobius gen. nov., and †Yarigobius gen. nov. are phenotypically similar to †Pseudolesueurigobius gen. nov. (see Table 1 for data on the fossils and Appendix Table for data on Lesueurigobius). The total number of vertebrae (27 vs. 28) differentiates †Pseudolesueurigobius gen. nov. from the three other new fossil genera, but not from Lesueurigobius. The main diagnostic character of †Pseudolesueurigobius gen. nov. is the sagitta shape (trapezoid, wide ventrally and comparatively narrow dorsally; see Fig. 9e1), which is very different from the otoliths of the aforementioned other extinct genera (Fig. 9a1–d1, f1–k1) and from otoliths of Lesueurigobius (Fig. 12). Also the lapillus shape is distinctive when compared to the other extinct genera (Fig. 10d1 vs. Fig. 10a1–c1, e1–g1), whereas it bears some similarity to the lapillus of Lesueurigobius (Fig. 10i1, j1) in its posteriorly tapered shape and the strong curvature of the medial margin.
Apart from the aforementioned characters, †Pseudolesueurigobius gen. nov. can be distinguished from †Katyagobius gen. nov. by the shorter distance between D1-spines V and VI (3.2–3.4% SL vs. 3.9–4.7% SL); the slightly shorter caudal peduncle (18.0–18.5% SL vs. 20.2–21.0% SL), and the relatively longer caudal fin (32.6–33.8% SL vs. 24.9–27.4% SL); from †Sarmatigobius gen. nov. by its relatively longer preanal distance (57.6–58% SL vs. 47.9% SL), a slightly shorter anal fin base (24.6–25.2% SL vs. 28.6% SL), and the more posterior insertion of the anal fin (two vertebrae behind D2 vs. opposite); and from †Yarigobius gen. nov. by the relatively longer caudal fin (33.4–33.8% SL vs. 25.0% SL), and a D1 pterygiophore formula starting with 3–2… (vs. 3–1…).
Notably, none of the morphometric or meristic characters of the skeleton differed between Pseudolesueurigobius gen. nov. and Lesueurigobius. The only differences refer to the scale size and the sagitta shape; Lesueurigobius has relatively larger scales (number of scales in the longitudinal row is 26–28 vs. about 46 in †Pseudolesueurigobius) and the sagitta shape in Lesueurigobius is almost rectangular (Figs. 9m1, 12) vs. trapezoid-to-rounded in †Pseudolesueurigobius (Fig. 9e1).
†Pseudolesueurigobius manfredi gen. et sp. nov.
Figures 5b, 6d-e, 7c, 8b, 9e, 10d, 11b; Table 1
Type material. Holotype, PIN 1306/72a, b, 65 mm SL; part and counterpart, each incomplete, but well preserved (part: posterior body and caudal fin in lateral view; counterpart: head in dorsolateral view, anterior half of body in lateral view); otoliths not preserved. Paratype, PIN 1306/81a, b, c. 41 mm SL; part and counterpart, each incomplete and partially damaged, in lateral view; part with left sagitta and right lapillus preserved in situ.
Type locality and age. Karpov Yar, Naslavcea, northern Moldova; lower Sarmatian.
Etymology. The species epithet is in honour of the husband of BR, Manfred Reichenbacher, for his patient and continuous support of our work on the fossil gobies from Naslavcea.
LSID ZooBank. This new species is registered under LSID urn:lsid:zoobank.org:act:1B5C41B5-5D55-43D0-A9BF-C4E88D66C994.
Diagnosis. SL up to 65 mm. Head moderately large (24.1–24.4% SL); preanal distance relatively long (57.6–58.0% SL); caudal peduncle moderately long (18.0–18.3% SL); caudal fin lanceolate and longer than head (33.4–33.8% SL); relatively short first spine of D1 (73% of length of second spine); spine of D2 relatively long (7.8–8.0% SL) and tapering to a filament; anal-fin spine and pelvic-fin spine of approximately the same size (3.3–5.0% SL); pelvic-fin spine length is about 34% of adjacent pelvic ray; relatively dense cover of ctenoid flank scales with not thickened posterior margins; about 46 scales in the longitudinal row. Other characters as described in the generic diagnosis.
General description. Medium-sized gobiid fish up to 65 mm SL (Fig. 5b); body cone-shaped and probably laterally compressed (being preserved in lateral view); head of moderate size (24.1–24.4% SL); anal fin inserting two vertebrae behind D2; caudal peduncle moderately long (18.0–18.3% SL); caudal fin lanceolate and long (33.2–33.8% SL). For further body proportions and meristic counts, see Table 1.
Neurocranium—The neurocranium is preserved in lateral view; it is relatively deep, but most of its bones are not well preserved. The eyes are relatively large (6.3–7.2% SL). The frontal bones are long and oriented obliquely to the body axis over the orbit, narrow between the orbits and broad posteriorly. The parasphenoid is a straight, thin rod with a broad posterior portion; the vomer is recognizable, but its shape cannot be traced. The ethmoid region is short. It is not clear whether scales are present on the head.
Jaws—The lower jaw is of moderate length (11.7% SL in the holotype, not measurable in the paratype); the lower jaw articulation is situated opposite to the middle of the orbit. The upper jaw bones are damaged, the maxilla is not recognizable. The premaxilla displays a fragment of the articular process and the beginning of the postmaxillary process, the ascending process is not preserved. The oral jaw dentition is only poorly preserved, but relatively robust, sharp conical teeth can be recognized.
Suspensorium, opercular apparatus and hyoid arch—Most of these bones are poorly preserved. A roughly triangular opercle and a crescent-shaped subopercle are detectable, while only fragments of the preopercle, branchiostegal rays and hyoid bars are present.
Branchial arches—Most of the bones of the branchial skeleton are not identifiable. Pharyngeal jaws are massive; the pharyngeal dentition is represented by relatively big, thick, and blunt teeth as well as by sharp, slender, conical teeth.
Vertebral column—There are 27 vertebrae, of which 10 are abdominal. The vertebral centra are constricted in the middle, with the centrum length (in both abdominal and caudal centra) being longer than the centrum height. Few parapophyses are recognizable. The length of the abdominal part of the vertebral column is 53% of the length of the caudal portion. The first caudal vertebra bears a haemal spine that is slightly approached towards the following haemal spine, and seems to be slightly shorter than the following haemal spine (Fig. 5b). At least seven pairs of slender ribs are present; the first five pairs are moderately long, and the last two relatively short; tiny epineurals are also present. The supraneurals are absent.
Pectoral girdle and fins—The posttemporal is incompletely preserved; its processes are long and slender. The cleithrum is robust, long and only slightly curved (Fig. 5b). The pectoral radials are broad, but their shapes are not recognizable. The pectoral fin length is 17.8% SL; it contains at least 12 thin rays.
Pelvic girdle and fins—The basipterygium is somewhat triangular. The pelvic fins seem to be close to each other (Fig. 6d); their length is 15.9–18.0% SL. Each pelvic fin contains a moderately long spine (3.8–5.0% SL) and five rays that are highly segmented and branched distally; proximally they seem to be unsegmented. The rays terminate distant from the origin of the anal fin.
Dorsal fins—The D1 has six slender spines, all of which taper into short filaments (Fig. 7c); length of first D1-spine approx. 73% of spine II; spines II to IV of similar lengths, spine IV is the longest (13.7% SL); spines V and VI decreasing in length (76% and 53% of spine II); the distance between spines V and VI is 1.5–1.6 times greater than that between spines IV and V; the pterygiophore formula is 3-22110. D2 inserts opposite to the last abdominal and first caudal vertebrae; it has a slightly bent, distally filamentous spine and 14 (paratype) or 16 (holotype) segmented and branched rays; the rays become progressively longer posteriorly and terminate above the last dorsal procurrent ray of the caudal fin (Fig. 8b).
Anal fin—The anal fin inserts below the third caudal vertebra, i.e., two vertebrae behind the origin of D2 (Fig. 5b). It comprises one moderately long, straight and slender spine (3.3–4.5% SL) and 14 rays; most of these rays are of similar length, and those farthest posterior terminate opposite to the first two caudal procurrent rays (Fig. 8b). The spine is supernumerary on the first pterygiophore. There are two anal-fin pterygiophores that insert before the haemal spine of the first caudal vertebra (Fig. 5b).
Caudal endoskeleton and fin—The caudal fin is wide, relatively long (33.4–33.8% SL) and lanceolate in shape (Fig. 5b). It is composed of 17 segmented principal rays, of which the outermost are not branched; 9 principal rays are present in the upper lobe. Six procurrent rays occur both dorsally and ventrally (visible in the holotype); the last two ventral procurrent rays display their forked bases. The caudal skeleton has two large hypural plates (HY1 + 2 and HY3 + 4), of which the upper is fused with the terminal centrum; hypural 5 is slender and short (Fig. 6e). There are imprints of a long, relatively broad parhypural that almost reaches the terminal centrum, and of a long, distally widened epural (Fig. 6e). The second preural vertebra (PU2) has a shortened neural spine, and a long, broad haemal spine, which supports the last ventral procurrent ray and the first two principal rays (Fig. 6e).
Otoliths—For measurements of the sagitta and lapillus, see Table 1, for the described characters, see Figs. 9e, 10d.
Sagitta: Inner (= medial) face flat; outer (= lateral) face convex, with centrally located, clearly delimited hump which takes up about one-third of the outer face; sagitta shape is trapezoid-to-rounded, with the ventral portion being distinctly wider than the dorsal part; dorsal margin relatively short, rounded, with slight concavity in the middle; posterior margin with distinct concavity in the midway, lower half with prominent posteroventral protrusion; ventral margin strongly symmetrically curved; preventral portion less protruding than posteroventral; anterior margin indented in the lower one-third and rounded above; ventral line shallow, anteriorly terminating opposite to the ostium tip, posteriorly ending at the tip of the posteroventral protrusion and distant from the end of the cauda; dorsal depression shallow; sulcus of ‘shoe-sole’ shape, moderately inclined (α = 9.8°); well-developed crista superior and crista inferior; the crista inferior is slightly thickened along the anterior cauda; ostium with triangular dorsal ostial lobe near the transition to the cauda; cauda oblong and terminally rounded.
Lapillus: Shape more or less ovate, tapering posteriorly; lateral margin relatively straight; medial margin strongly convex; cranial suture moderately well defined, sulculus curved and relatively short. Further details cannot be reported as the lapillus unfortunately disintegrated during extraction from the specimen.
Scales—The flank scales are ctenoid, round and ovate and relatively thin, their ctenii are short (Fig. 11b1); 5–8 relatively weak radii are present (Fig. 11b2). Scale number in longitudinal row is about 46 (based on the paratype). The belly and predorsal scales are smaller than the flank scales, whether or not they are also ctenoid cannot be decided. Thin scales also cover the bases of the caudal-fin rays (Fig. 8b).
Genus †Sarmatigobius gen. nov.
Type species. †Sarmatigobius compactus gen. et sp. nov. (Figs. 5c, 7e, 8c, 9f-g, 10e, 11c).
Other species. †Sarmatigobius iugosus (Schwarzhans, Brzobohatý and Radwańska, 2020) comb. nov. (Figs. 5d, 6c, 7d, 9h) from the upper Badenian to lower Sarmatian of the Central Paratethys and Moldova.
Etymology. The name refers to the distribution of this taxon (Sarmatian) and its general similarity to members of the Gobiidae. Gender masculine.
LSID ZooBank. This new genus is registered under urn:lsid:zoobank.org:act:076CD640-BCFE-410B-835F-59FBD934D5EE.
Stratigraphic range. Upper Badenian to Lower Sarmatian.
Diagnosis. Medium-sized fish of 54–64 mm SL; head moderately large (21.7–24.7% SL); body probably laterally compressed (being preserved in lateral view); D1 and D2 widely separated; anal fin inserted opposite to D2; relatively short preanal distance (47.9% SL); relatively long anal-fin base (28.6% SL); caudal peduncle moderately long (18.5% SL); caudal fin lanceolate and longer than head (approx. 32.6% SL); length of abdominal part of vertebral column approx. 50% of length of caudal part of vertebral column. Number of vertebrae 28 (10 + 18); D1 with six spines, first five spines with short distal filaments; D2 with straight, relatively long spine (7.2% SL) and 16 segmented rays; anal fin with thin, straight, relatively short spine (3.5% SL) and 15 segmented rays. Pectoral fin with up to 14 rays; pelvic fins with spine and five rays; ends of pelvic rays distant from anal-fin origin. Caudal fin with 17 segmented rays, 9 rays in the upper lobe. Relatively dense cover of ctenoid (in type species) or probably cycloid scales (in †S. iugosus) on body.
Otoliths—Sagitta of squarish-to-ventrally rounded shape, with very deep dorsal depression that extends to the dorsal margin; sulcus ‘shoe-sole’-shaped and slightly inclined (α = 5.0–7.6°), with prominent subcaudal iugum. Lapillus of ovate shape in ventral view; in lateral view wedge-shaped, with the thickest part located posteriorly.
Differential diagnosis. With respect to the presence of a longish caudal fin, high number of rays in the D2 and anal fin, and general proportions of head and body, Lesueurigobius Whitley, 1950 and the three other new fossil genera described in this study, i.e., †Katyagobius gen. nov., †Pseudolesueurigobius gen. nov., and †Yarigobius gen. nov. are phenotypically similar to †Sarmatigobius gen. nov. (see Table 1 for data on the fossils and Appendix Table for data on Lesueurigobius). Three skeleton-based characters clearly differentiate †Sarmatigobius gen. nov. from these, namely its relatively shorter preanal distance (47.9% SL vs. 54.3–58.0% SL), a longer anal-fin base (28.6% SL vs. 23.2–25.3% SL), and the insertion of the anal fin opposite to D2 (vs. 1.5–2 vertebrae behind). Moreover, †Sarmatigobius gen. nov. has a very distinctive sagitta morphology (in terms of overall shape, dorsal depression, shallow sulcus inclination angle; see diagnosis), and also the wedge-shaped lateral view of the lapillus is unique (see diagnosis).
Remarks. The otoliths of a species originally named †Hesperichthys iugosus Schwarzhans, Brzobohatý and Radwańska, 2020 share with the otoliths of †Sarmatigobius nov. gen. a squarish-to-rounded shape, a very deep dorsal depression and a weakly inclined sulcus. No skeleton has been reported for †H. iugosus; it was defined on the basis of three otoliths from the upper Badenian to lower Sarmatian of the Central Paratethys (Schwarzhans et al. 2020b). Its assignment to the genus †Hesperichthys Schwarzhans, Ahnelt, Carnevale and Japundžić, 2017 was based on the similarity with otoliths of †Hesperichthys reductus Schwarzhans, Ahnelt, Carnevale and Japundžić, 2017, of which the skeleton is also known. According to the original description of the skeleton of †Hesperichthys in Schwarzhans et al. (2017a), it is obvious that †Hesperichthys and †Sarmatigobius gen. nov. differ from one another in many characters and cannot represent the same genus. For instance, there are four interneural spaces between the D1 and D2 in †Hesperichthys (vs. one in †Sarmatigobius gen. nov.), the number of abdominal vertebrae is 11 (vs. 10), there are nine soft rays in the D2 (vs. 16), and ten soft rays are present in the anal fin (vs. 15). The otoliths found in situ in the holotype and paratype of †H. reductus clearly differ from those of †Sarmatigobius gen. nov. insofar as the sulcus shows no clear boundary/distinction between ostium and cauda (vs. clear separation), a dorsal depression is lacking (vs. strongly developed) and the outer face is strongly convex (vs. moderately convex) (Schwarzhans et al. 2017a: fig. 11f, g). The superficial similarity between the otoliths of †H. reductus and †Sarmatigobius gen. nov. is mainly attributable to the low inclination angle of the sulcus, which is common to both. Schwarzhans et al. (2017a) also assigned some isolated otoliths from the Sarmatian deposits to †H. reductus. Among them, one displays a clear separation of the ostium from the cauda and a deep dorsal depression that extends to the dorsal margin (see Schwarzhans et al. 2017a: fig. 11h); this single otolith is here tentatively assigned to †Sarmatigobius sp.
†Sarmatigobius compactus gen. et sp. nov.
Figures 5c, 7e, 8c, 9f, g, 10e, 11c
Type material. Holotype; PIN 5274/36a, b, 53.9 mm SL. Preserved as part and counterpart, with both sagittae and right lapillus in situ; part almost completely preserved, counterpart comprises well preserved head and anteriormost portion of body.
Type locality and age. Karpov Yar, Naslavcea, northern Moldova; lower Sarmatian.
Etymology. The species name refers to the compact body shape of this species.
LSID ZooBank. This new species is registered under urn:lsid:zoobank.org:act:478D15FB-63B2-40E6-B563-F062DA145D5B.
Diagnosis. Differentiated from the only other species currently known, †S. iugosus (Schwarzhans et al. 2020a, b), by robust oral jaw teeth (vs. very slender), a slightly longer head (24.7% SL vs. 21.7% SL), a greater body depth (19.3% SL vs. 11.9% SL), a slightly shorter distance between the D1-spines V and VI (3.0% SL vs. 3.3% SL), and the presence of ctenoid scales (vs. probably cycloid). There may be further differences between the skeletons of the two species, which are currently not recognizable because the preservation of †S. iugosus is only moderate. The differences between the sagittae of the two species include: almost flat or slightly rising dorsal margin in †S. compactus gen. et sp. nov. (vs. slightly concave in †S. iugosus); no prominent protuberance at the posterior end of the dorsal margin (vs. present); and presence of ovate, very thick subcaudal iugum (vs. longish and less thick).
General description. Medium-sized gobiid fish; SL 53.9 mm (Fig. 5c). Body preserved in lateral view (Fig. 5c2), head in dorsolateral view (Fig. 5c1). Body slightly cone-shaped; head of moderate size (24.7% SL); D2 and anal fin inserting opposite to each other; relatively long caudal peduncle (18.5% SL); caudal fin lanceolate and longer than head (32.6% SL). For further body proportions and meristic counts, see Table 1.
Neurocranium—The neurocranium is preserved in dorsolateral view and seems to be moderately deep, but individual bones of the braincase are barely recognizable. The parasphenoid borders the lower margin of the orbit; it is straight, and relatively narrow, with a broad posterior portion. The vomer is rounded anteriorly. The ethmoid part of the neurocranium is relatively short. Head scales are not present (or not preserved).
Jaws—The mouth gape is moderately wide; the lower jaw articulation is situated slightly anterior to the middle of the orbit. The maxilla is slender and elongate, slightly broader posteriorly and somewhat bent in its anterior portion. The premaxilla has a very thin ascending process and a broad articular process; the posterior part of the premaxilla is poorly preserved. Premaxillary teeth seem to be strong and robust. The dentary is narrow and long; it bears relatively large and robust teeth. Further details of the jaws are not recognizable.
Suspensorium, opercular apparatus and hyoid arch—The suspensorium bones are poorly preserved. The quadrate is a roughly triangular bone with a deep and wide indentation in its posterodorsal portion and a strong, thick and pointed posterior process. Bones of the opercular region are too poorly preserved to be described. The hyoid bar (ceratohyal + epihyal) is relatively straight, the anterior portion of the ceratohyal is slightly broadened; the posterior portion of the ceratohyal is not clearly discernible; the epihyal is triangular. The interhyal is not recognizable. A few branchiostegal rays are visible (Fig. 5c1), but the total complement of branchiostegal rays cannot be specified.
Branchial arches—The individual bones of the branchial skeleton are not identifiable. The pharyngeal teeth are relatively robust; some of the teeth are pointed, others are blunt.
Vertebral column—There are 28 vertebrae, of which 10 are abdominal. Vertebral centra are constricted in the middle; centrum length exceeds the centrum height. The parapophyses are well developed. The length of the abdominal part of the vertebral column corresponds to approx. 50% of the length of the caudal part. The haemal spine of the first caudal vertebra is somewhat shorter than those behind it; all the haemal spines are more or less equally inclined (Fig. 5c2). Ribs are present from the second to the last abdominal vertebra; they are slender and relatively long. In the region of the ribs, a few slender epineural bones are visible. The supraneurals are absent.
Pectoral girdle and fins—Only the main body of the posttemporal is visible. The supracleithrum is elongate and narrow. The cleithrum is stout, long and only slightly curved; the coracoid is not preserved. Three radial bones, roundish-to-square in shape, are preserved. The number of the pectoral-fin rays is 14, but their full extents cannot be discerned.
Pelvic girdle and fins—The pelvic bone is located slightly anterior to the radials of the pectoral fin. The pelvic fins are not well preserved, but a spine and five soft rays are recognizable. The pelvic-fin rays are relatively thick and distally branched; their full lengths cannot be clearly traced, but they terminate at some distance from the anal-fin origin.
Dorsal fins—The D1 has six slender spines that taper into long filaments; the last spine is the shortest and lies quite close to the preceding one (3.0% SL distance between them); the pterygiophore formula is 3-22110 (Fig. 7e). The D2 inserts distantly from the D1, above the second caudal vertebra (Fig. 5c2). It consists of a slender spine that narrows to a long filament and 16 segmented and branched rays; the posteriormost rays end above the first two procurrent caudal-fin rays (Fig. 8c).
Anal fin—The anal fin inserts below the second caudal vertebra. It comprises a thin, straight and short spine (3.5% SL) and 15 segmented and branched rays; the posteriormost rays terminate opposite to the first two procurrent caudal-fin rays (Fig. 8c). The number of the anal-fin pterygiophores inserting anterior to the haemal spine of the first caudal vertebra is not clear, but seems to be two.
Caudal endoskeleton and fin—The caudal fin is longish (32.6% SL) and probably lanceolate. It is composed of 17 segmented principal rays; 9 principal rays are present in the upper lobe. Six procurrent rays occur both dorsally and ventrally. The caudal skeleton has two large hypural plates (HY1 + 2 and HY3 + 4), of which the upper is fused with the terminal centrum; hypural 5 is slender. Due to the dense scale cover, neither the parhypural nor epural are recognizable. The neural spine of PU2 is shorter than the preceding spines and seems to be duplicated. The haemal spine of PU2 is long, plank-like, and oriented obliquely to the caudal fin, where it supports two or three principal caudal-fin rays; an additional (duplicated) shorter haemal spine occurs slightly behind the middle of the PU2 centrum (Fig. 8c).
Otoliths—For measurements of the sagittae and lapillus, see Table 1, for the described characters, see Figs. 9f, g, 10e.
Sagitta: Inner (= medial) face flat to weakly convex; outer (= lateral) face convex, with rounded hump located at and slightly above the centre; general shape squarish-to-ventrally rounded; ventral portion wider than dorsal portion; dorsal margin weakly convex and slightly rising posteriorly; no preventral or posterodorsal (or any) projections; ventral line deep and extending up to the sulcus tip and sulcus end, respectively; deep dorsal depression extending to the dorsal margin; sulcus very slightly inclined, with wide ostium and elongate cauda; cauda shorter than ostium, with roundish and very thick subcaudal iugum.
The right and left sagittae show some asymmetry, the dorsal margin being slightly more ascending in the right than in the left sagitta, while the posteroventral margin is asymmetrically curved in the right, but regularly curved in the left sagitta, and the length/height ratio also differs between the two (0.99 in the right, 1.06 in the left sagitta).
Lapillus: The single preserved right lapillus is rounded to ovate; in ventral view it shows a clear cranial suture, curved sulculus, and a more or less V-shaped linea basalis on the posterior half; in lateral view, it is wedge-shaped, with the thickest part lying posteriorly.
Scales—All scales are ctenoid. Flank scales are relatively large, their shape is mostly ovate, and a slight protuberance can occur in the middle of the posterior margin (Fig. 11c). The scale surface is relatively smooth, apart from the thickened posterior margin; several circuli and five weak radii can be observed. Scales above the anal fin display relatively long ctenii; scales beneath the D2 seem to have shorter ctenii. Scale number in the longitudinal row is about 45. Predorsal and belly scales are round, thin and noticeably smaller than the flank scales. Scales also cover the base of the caudal-fin rays (Fig. 8c).
†Sarmatigobius iugosus (Schwarzhans, Brzobohatý and Radwańska, 2020) comb. nov.
Figures 5d, 6c, 7d, 9h
* 2020 Hesperichthys iugosus Schwarzhans, Brzobohatý and Radwańska: p. 161, pl. 9, figs. 13–14 [otoliths only].
Material examined. Specimen PIN 5274/38a, b, approx. 64 mm SL; preserved as part and counterpart; part fragmented and highly incomplete; counterpart (Fig. 5d) with well preserved head exposing a left sagitta in situ (right sagitta has been extracted and is shown in Fig. 9h) and relatively well preserved anterior half of the body.
Locality and age. Karpov Yar, Naslavcea, northern Moldova; lower Sarmatian.
General description. Medium-sized gobiid fish; approx. 64 mm SL; body and head preserved in lateral view. Body elongate and slender; head of moderate size (21.7% SL); body depth at origin of anal fin 11.9% SL; base of D2 relatively long (34.8% SL); pectoral fin of moderate length (15.1% SL). For further body proportions and meristic counts, see Table 1.
Neurocranium—The neurocranium is preserved roughly in lateral view and seems to be moderately deep. The eyes are relatively large; horizontal diameter of the orbit almost equals the snout length. The long frontal bones are oriented almost horizontally to the body axis over the orbit; they are relatively narrow between the orbits and become broader posteriorly. The parasphenoid borders the lower margin of the orbit; it is straight, relatively narrow, with a broad posterior portion. The vomer is recognizable, and is rounded anteriorly. The ethmoid part of the neurocranium is relatively short. Head scales are not recognizable.
Jaws—The mouth gape is moderately wide; the lower jaw articulation is situated slightly anterior to the middle of the orbit (Fig. 5d). The maxilla is slender and elongate, slightly broader posteriorly and somewhat bent in its anterior portion. The premaxilla has a very thin ascending process, a broader articular process and a moderately developed postmaxillary process. Premaxillary teeth are slender, small, conical, differ somewhat in size and are multiserial. The dentary is narrow and long, it has a moderately developed coronoid process; the dentary bears both large (‘caniniform’) and small slender conical teeth (Fig. 6c). The anguloarticular is moderately deep at the retroarticular process.
Suspensorium, opercular apparatus and hyoid arch—Not all of the suspensorium bones are readily recognizable. The symplectic is a robust rod in its lower portion; the remains of the metapterygoid are preserved. The quadrate is a roughly triangular bone with a deep and wide indentation in its posterior portion and a strong, thick and pointed posterior process. The ectopterygoid is a relatively long bone, almost straight and tapered posteriorly. There is no entopterygoid. The palatine is T-shaped, its maxillary process is slightly bigger than its ethmoidal process (Fig. 6c); the palatine shaft is tapered posteriorly and it is not clear whether it reaches the quadrate. The preopercle is strongly curved and crescent-shaped. The opercle is triangular and tapered ventrally; the subopercle is slightly larger than the opercle, whereas the interopercle is not recognizable. The hyoid bar (ceratohyal + epihyal) is relatively straight; the anterior portion of the ceratohyal is slightly broadened, while its posterior portion is not clearly visible; the epihyal is triangular. The interhyal is not recognizable. A few branchiostegal rays are visible (Fig. 5d), but their total number cannot be determined.
Branchial arches—The individual bones of the branchial skeleton are not identifiable. Both thin, cylindrical and sharp, as well as large, cylindrical and somewhat blunt teeth are recognizable in the pharyngeal jaws.
Vertebral column—Ten abdominal vertebrae are present, but the total number of vertebrae is not definable because of the incompleteness of the specimens. The vertebral centra are somewhat elongated and constricted in the middle; the vertebral spines are moderately long and almost straight. Ribs are slender and relatively long; these are strongly inclined posteriorly. Only a few of the slender epineurals are partially preserved.
Pectoral girdle and fins—Only the main body of the posttemporal is visible. The supracleithrum is elongate and narrow. The cleithrum is stout, long and only slightly curved; the coracoid is not preserved. The radial bones are poorly preserved; the number of pectoral-fin rays is at least 12, and they are moderately long (15.1% SL).
Pelvic girdle and fins—The pelvic girdle is not preserved. The pelvic-fin rays are disarticulated, relatively thick and distally branched.
Dorsal fins—The D1 contains six slender spines (Figs. 5d, 7d), of which at least the four anteriormost ones taper distally into filaments; the last spine is shortest and close to the preceding one (3.3% SL); the pterygiophore formula is not recognizable. The D2 is widely separated from the D1 (Figs. 5d, 7d), with a vacant interneural space between them; the D2 has a relatively robust, straight spine, its posterior part is missing because of incomplete preservation, but the number of soft rays is definitely relatively high.
Anal fin—The anal fin is not completely preserved, but the number of its rays seems to be relatively high.
Caudal endoskeleton and fin—Details of the caudal fin are not recognizable, owing to the fragmentary preservation.
Otoliths—For measurements, see Table 1, for the described characters, see Fig. 9h. The species-specific characters of the sagitta include a somewhat depressed dorsal margin that bears a rounded protuberance at its posterior end, and the occurrence of a prominent and relatively long subcaudal iugum. All other characters are as described above for †S. compactus gen. et sp. nov.
Scales—The scales appear to be cycloid, but minute spinules are dispersed through the body, and may represent ctenii that were originally loosely connected to the scale margins. The flank scales are relatively large; the belly scales are smaller than the flank scales; scales also overlie the base of the caudal-fin rays. Predorsal scales are smaller than the flank scales, very thin and cycloid.
Remark. See differential diagnosis for †S. compactus gen. et sp. nov. for differences between the two species.
Genus †Yarigobius gen. nov.
Type species. †Yarigobius decoratus gen. et sp. nov. (Figs. 5f, 7f, 8d, 9k, l, 10f,g, 11d).
Other species. †Yarigobius naslavcensis gen. et sp. nov. (Figs. 5e, 7g, 8e, 9i, j, 11e).
Etymology. The generic name refers to the locality in which this new genus was discovered (Karpov Yar, Moldova) and its general similarity to members of the family Gobiidae. Gender masculine.
LSID ZooBank. This new genus is registered under urn:lsid:zoobank.org:act:DEE7C882-8602-4E54-B958-2E5AB7FE631B.
Stratigraphic range. Lower Sarmatian.
Diagnosis. Relatively small to medium-sized gobiid fish, 38.7 to 63.2 mm SL; head moderately large (23.7–24.3% SL); body probably laterally compressed (as preserved in lateral view); body depth at origin of D1 is comparatively large (21.4–21.7% SL); pre-anal distance relatively long (54.3–58.0% SL); anal fin inserted one to two vertebrae behind insertion of D2; anal-fin base relatively short (23.2–25.3% SL); pelvic fins relatively long (20.9–22.9% SL); pelvic-fin spine relatively short (4.6–5.2% SL and 35–36% of adjacent ray); relatively long caudal part of vertebral column (52.7–53.5% SL) and caudal peduncle (19.4–23.3% SL); caudal fin lanceolate and about as long as head (25.0% SL). Number of vertebrae 28–29 (10 + 18–19). Dorsal fins widely separated. D1 with six or seven slender, distally filamentous spines; D1 pterygiophore formula starting with a single first pterygiophore (3–1…, 2–1…); D2 with one spine and 14–16 segmented rays; anal fin with one spine and 13–14 segmented rays. Pectoral fin with about 15 rays (not clearly discernible). Pelvic fins with spine and five rays; pelvic rays end some distance from anal-fin origin. Caudal fin with 16 to 17 segmented rays, eight to nine rays in the upper lobe. Scales cycloid (type species) or ctenoid. In addition, the following characters of the saccular otoliths (sagittae) are, in combination, diagnostic for this genus: sagitta shape rounded-to-rectangular, with ventral portion being slightly wider than dorsal portion; weakly pronounced, rounded posterodorsal and preventral projections and slightly protruding posteroventral portion; ventral margin slightly undulated; shallow, clearly delimited dorsal depression; sulcus of ‘shoe-sole’ shape, moderately to distinctly inclined (α = 6.5–18.5°); clear separation into elongate ostium and short cauda. Lapillus with almost straight dorsal side and moderately convex ventral side; ovate shape in ventral view; shape in lateral view is elongate anteriorly and rounded-to-rectangular posteriorly.
Differential diagnosis. The most phenotypically similar genera with respect to the presence of a longish caudal fin, high number of rays in the D2 and anal fin, and the general proportions of head and body are Lesueurigobius Whitley, 1950 and the three other new fossil genera described in this study, i.e., †Katyagobius gen. nov., †Pseudolesueurigobius gen. nov., and †Sarmatigobius gen. nov. (see Table 1 for data on the fossils and Appendix Table for data on Lesueurigobius). The presence of a slightly longer caudal part of the vertebral column (52.7–53.5% SL vs. 49.2–50.5%% SL) and a pterygiophore formula starting with a single pterygiophore (vs. two) differentiates †Yarigobius gen. nov. from these genera. A further diagnostic character of †Yarigobius gen. nov. is a rounded-to-rectangular sagitta with slight posterodorsal and preventral projections (vs. no projections in the sagittae of the other fossil genera [see Fig. 9], and vs. a well developed posterodorsal portion or projection in Lesueurigobius [see Fig. 12]). Also the lapillus shape is distinctive, when compared to the other new fossil genera (see Fig. 10). The lapillus shows similarity to the lapillus of Gobius (Fig. 10h) in both ventral and lateral view, but the dorsal side is straight in †Yarigobius gen. nov. (vs. convex in Gobius).
Further characters of †Yarigobius gen. nov. that differentiate it from †Katyagobius gen. nov. include: greater body depth at origin of D1 (21.4–21.7% SL vs. 17.7–18.5% SL); slender D1 spines (vs. robust); slightly longer pelvic fins (20.9–22.9% SL vs. 16.1–17.1% SL); relatively shorter pelvic-fin spine (4.6–5.2% SL + 35–36% of adjacent ray vs. 6.0–6.5% SL + 56–66% of adjacent ray). Characteristics of †Yarigobius gen. nov. that separate it from †Pseudolesueurigobius gen. nov. are its 18–19 caudal vertebrae (vs. 17) and a relatively shorter caudal fin (25.0% SL vs. 33.4–33.8% SL). Traits that distinguish †Yarigobius gen. nov. from †Sarmatigobius gen. nov. are the relatively longer preanal distance (54.3–58.0% SL vs. 47.9% SL); relatively shorter anal-fin base (23.2–25.3% SL vs. 28.6% SL); and an anal fin that is inserted 1.5–2 vertebrae behind the insertion of the D2 (vs. opposite).
†Yarigobius decoratus gen. et sp. nov.
Figures 5f, 7f, 8d, 9k, l, 10f, g, 11d
Type material. Holotype, PIN 5274/76a, b, 63.2 mm SL. Well preserved part and slightly damaged counterpart, with left and right otoliths (sagittae and lapilli) preserved in situ.
Type locality and age. Karpov Yar, Naslavcea, northern Moldova; lower Sarmatian.
Etymology. The species name refers to the presence of some enlarged cycloid scales on the posteriormost portion of the body, which appear to ‘decorate’ the fish.
LSID ZooBank. This new species is registered under urn:lsid:zoobank.org:act:14ED4CB9-F03D-4122-B2F8-5DD41EFFD94E.
Diagnosis. Differentiated from the only other species of this genus currently known, †Y. naslavcensis gen. et sp. nov. by a relatively shorter lower jaw (7.9% SL vs. 10.3% SL); a longer caudal peduncle (23.3% SL vs. 19.4% SL); a greater body depth at the origin of the anal fin (20.6% SL vs. 16.8% SL); a wider separation between D1 and D2 (9.5% SL vs. 4.7% SL); six D1 spines (vs. seven); and presence of cycloid scales (vs. ctenoid), some of which are enlarged. The sagitta of †Y. decoratus gen. et sp. nov. is longish (vs. slightly higher than long in †Y. naslavcensis) and its posteroventral protrusion is slightly angular (vs. rounded).
General description. Medium-sized gobiid fish; 63.2 mm SL (Fig. 5f). The body is preserved in lateral view and moderately elongate; the head is seen in dorsolateral view and moderately large (23.7% SL); the D2 inserts one vertebra before the anal fin; the caudal peduncle is relatively long (23.3% SL); the caudal fin is longish and about as long as the head (25.0% SL). For further body proportions and meristic counts, see Table 1.
Neurocranium—The neurocranium is preserved in dorsolateral view; it is relatively deep, but most of its bones are not sufficiently well preserved to be described. The parasphenoid is straight, relatively narrow, with a broad posterior portion; it borders the lower margin of the apparently relatively large orbit. The vomer is not clearly recognizable. The ethmoid part of the neurocranium is relatively short. Head scales are either not present or not preserved.
Jaws—The lower jaw is of moderate length (7.9% SL); the lower jaw articulation is situated slightly behind the middle of the orbit. The maxilla seems to be slender and moderately expanded posteriorly. The premaxilla is a robust bone, with a moderately slender ascending process and a wide articular process. The dentition comprises both large and small conical teeth.
Suspensorium, opercular apparatus and hyoid arch—The suspensorial bones are poorly preserved and hardly recognizable. The opercular bones are not completely preserved; the preopercle is rather slender and slightly curved, the opercle is roughly triangular and the subopercle is elongate. The hyoid bars are poorly visible; five branchiostegal rays are recognizable, of which the first is very slender, whereas the others are strong.
Branchial arches—The individual bones of the branchial skeleton are hardly identifiable. The pharyngeal jaws are robust and their dentition is represented by relatively large, stout, and blunt teeth as well as by long, slender, conical, pointed teeth.
Vertebral column—There are 29 vertebrae, of which 10 are abdominal (only 9 abdominal vertebrae are recognizable, but based on the space between the first visible centrum and the basioccipital it can be assumed that the anteriormost vertebra is not preserved). The vertebral centra are constricted in the middle; the centrum length is slightly longer than the centrum height. The parapophyses are clearly recognizable in the posterior abdominal vertebrae. The length of the caudal part of the vertebral column is 53.5% SL; the length of the abdominal part of the vertebral column is equivalent to 49.1% of the caudal part. The haemal spine of the first caudal vertebra is slightly shorter than those of the following caudal vertebrae (Fig. 5f); all the haemal spines are equally inclined, apart from the spines of preural vertebrae 2 and 3, which are more strongly inclined. Ribs are slender and moderately long; ribs extend from the third to the last abdominal vertebra. In the region of the ribs, a few epineural bones are visible. The supraneurals are absent.
Pectoral girdle and fins—The pectoral girdle is slightly disarticulated. The posttemporal has a relatively broad body and long, slender processes. The cleithrum is relatively broad, long and only slightly curved, and a small triangular coracoid is present. The pectoral fin is not preserved.
Pelvic girdle and fins—The basipterygium is somewhat triangular. The pelvic fins seem to be close to each other, their length is about 22.9% SL. Each pelvic fin contains a relatively short spine (5.2% SL, 35.8% of the adjacent ray) and five rays that are highly segmented and branched distally; proximally they seem to be unsegmented. The rays terminate at some distance from the origin of the anal fin (Fig. 5f).
Dorsal fins—The D1 has six slender spines (Figs. 5f, 7f), which taper gradually into especially slender filaments; the last spine is the shortest, lies slightly distant from the preceding one and much further (9.5% SL) from the D2 spine. The pterygiophore formula seems to be 3-13110 (visible in the counterpart), but the neural spine of the fifth vertebra is slightly distorted and the formula could also be 3-12210. The D2 inserts above the second caudal vertebra. It consists of a slender spine with a short filament, and 16 segmented and branched rays; the first soft rays have about the same length, the posterior ones become longer and form a slightly pointed lobe; their distal ends terminate above the anterior procurrent caudal-fin rays.
Anal fin—The anal fin inserts below the third caudal vertebra, i.e., one vertebra behind the origin of the D2. It comprises one relatively long (6.3% SL), slender, slightly curved spine and 14 rays. Overall, the anal fin is similar in shape and size to the D2 (Fig. 5f); the posteriormost rays of the anal fin also reach the caudal-fin origin; they terminate opposite to the first two procurrent caudal rays (Figs. 5f, 7d). The spine is supernumerary on the first pterygiophore. This pterygiophore seems to be the only one that inserts before the haemal spine of the first caudal vertebra.
Caudal endoskeleton and fin—The caudal fin is wide, of moderate length (25.0% SL) and longish to lanceolate. It is composed of 17 segmented principal rays, the outermost rays are unbranched; 9 principal rays are found in the upper lobe. Six procurrent rays are present both dorsally and ventrally, and display their forked bases (Fig. 8d). The caudal skeleton comprises two large hypural plates (HY1 + 2 and HY3 + 4), of which the upper is fused with the terminal centrum; hypural 5 is slender. The parhypural is relatively long and does not reach the terminal centrum; the epural seems to be very broad. The neural spine of PU2 is slightly broader and shorter than the preceding spines. The haemal spine of PU2 is long and distally expanded (Fig. 8d).
Otoliths—For measurements of the sagitta and lapillus, see Table 1, for the described characters, see Figs. 9k, l, 10f, g.
Sagitta: Inner (= medial) face flat; outer (= lateral) face convex, with roundish hump situated in the central and posteroventral region; general shape of sagitta longish-to-rectangular with rounded, relatively small posterodorsal and preventral projections; ventral portion of sagitta slightly wider than the dorsal; dorsal margin highest in its posterior third, smoothly declining anteriorly; posterior margin indented; ventral margin slightly undulated; ventral line relatively broad and shallow, its anterior portion terminates close to the sulcus tip, its posterior part ends somewhat distant from the sulcus end; dorsal depression shallow and clearly delimited from dorsal margin; sulcus of ‘shoe-sole’ shape and moderately inclined (α = 6.5–8.5°); ostium longer than cauda; ostium with rounded-to-triangular dorsal lobe near the transition to the cauda and weakly curved ventral lobe; cauda relatively short and roundish.
The right and left sagittae (of the holotype) show slight asymmetry: the anterodorsal margin exhibits a small angular projection (right sagitta) or is weakly rounded (left sagitta); the anterior margin is notched (right sagitta) or faintly concave (left sagitta); and the crenulation of the ventral margin is mainly in the anterior half (right sagitta) or in the middle (left sagitta).
Lapillus: Both lapilli are preserved in the holotype. In ventral view their shape is ovate; a cranial suture and a curved sulculus are well developed; a well-defined linea basalis extends across the posterior half of the lapillus; the shape of the linea basalis is V-like, with a longer and slightly undulating medial part and a shorter lateral segment. In lateral view, the lapilli present a slightly sinuous lateral margin and a slender anterior portion; the remaining portion of the dorsal side is straight and that of the ventral side is moderately convex.
Scales—All scales are cycloid. The relatively large flank scales are thickened along their posterior margin and exhibit a rounded angle in the middle of the posterior border; overall their shape is aliform (Fig. 11d3). About 6–7 radii extend from the focus, which is located in the posterior part of the scale, to the anterior scale margin (Fig. 11d1). Above and below the radii the scale is relatively smooth and numerous circuli are visible. The scale number in longitudinal row is about 40. At the dorsal and ventral margins of the posterior caudal peduncle, a few enlarged scales are present (Figs. 5f, 8d, 11d2); they seem to lack any radii. The predorsal scales are very small; the belly scales are rounded, thin and smaller than the flank scales. Scales also cover the base of the caudal-fin rays (Fig. 8d).
Coloration—The holotype reveals a dense, dark pigmentation in the distal portions of the dorsal, anal and pelvic fins. The most prominent pigmentation is present on the anal fin (Fig. 5f).
†Yarigobius naslavcensis gen. et sp. nov.
Figures 5e, 7g, 8e, 9i, j, 11e
Type material. Holotype, PIN 1306/71, 38.7 mm SL; an almost complete, well-preserved specimen in a single plate, end of caudal fin missing; both sagittae preserved in situ (lapilli not preserved).
Type locality and age. Karpov Yar, Naslavcea, northern Moldova; lower Sarmatian.
Etymology. The species is named after the township Naslavcea, Moldova, in the vicinity of the type locality.
LSID ZooBank. This new species is registered under urn:lsid:zoobank.org:act:35847C32-4BEA-4FC1-A06F-686C41869B41.
Diagnosis. As for genus. Differentiated from the only other species currently known, †Y. decoratus gen. et sp. nov. by a relatively longer lower jaw (10.3% SL vs. 7.9% SL), a shorter caudal peduncle (19.4% SL vs. 23.3% SL), a smaller body depth at the origin of the anal fin (16.8% SL vs. 20.6% SL), a shorter distance between D1 and D2 (4.7% SL vs. 9.5% SL), seven D1-spines (vs. six) and the presence of ctenoid scales (vs. cycloid), with no enlarged scales. The sagitta of †Y. naslavcensis gen. et sp. nov. is slightly higher than long (vs. longish in †Y. decoratus) and its posteroventral protrusion is rounded (vs. slightly angular).
General description. Relatively small gobiid fish of 38.7 mm SL (Fig. 5e); the body is elongate, only slightly tapering posteriorly; probably laterally compressed (as preserved in lateral view); the head is of moderate size (24.3% SL); the anal fin inserts two vertebrae behind D2; the caudal peduncle is moderately long (19.4% SL). For further body proportions and meristic counts see Table 1.
Neurocranium—The neurocranium is deep; the eyes are relatively large (5.9% SL), and the ethmoid region very short. The frontal bones are long and oriented obliquely to the body axis over the orbit, narrow between the orbits and broad posteriorly. The parasphenoid is a straight, thin rod with a broad posterior portion; the vomer is recognizable, but its shape is not clear. The ethmoid region is short. Whether scales are present on the head cannot be decided.
Jaws—The lower jaw is relatively long (10.3% SL); the jaw joint is located opposite the middle of the orbit (Fig. 5e). The dentary is narrow anteriorly and becomes deeper posteriorly; it bears at least two rows of variously sized teeth. The anguloarticular has a relatively strong retroarticular process; the groove in which the Meckelian cartilage lay is traceable. The upper jaw bones are damaged; the preserved parts of the premaxilla bear a postmaxillary process; the maxilla is not preserved. Some slender and conical premaxillary teeth are recognizable.
Suspensorium, opercular apparatus and hyoid arch—The suspensorium and opercular bones are poorly preserved. The symplectic is a robust rod. Five branchiostegal rays are preserved in almost anatomical connection with the hyoid bar; the shape of the hyoid bar is unclear.
Branchial arches—Most of the bones of the branchial skeleton are not identifiable. The large pharyngeal jaws bear slender, pointed teeth of slightly different sizes.
Vertebral column—There are 28 vertebrae, of which 10 are abdominal. The vertebral centra are constricted in the middle; the centrum length is slightly longer than the centrum height. Only a few parapophyses are recognizable. The length of the abdominal part of the vertebral column is 52.7% that of the caudal part. The first caudal vertebra bears a haemal spine that is slightly inclined towards the following haemal spine, but is as long as the other haemal spines (Fig. 5e); all the haemal spines are more or less equally inclined. At least eight pairs of slender ribs are present; the first six pairs are moderately long, and the last two pairs are relatively short; tiny epineurals are also present. Supraneurals are absent.
Pectoral girdle and fins—The posttemporal is incompletely preserved. The cleithrum is robust, long and only slightly curved. Only the slightly displaced base of the pectoral fin is preserved; the number and length of its rays are unknown.
Pelvic girdle and fins—The length of the pelvic fins is 20.9% SL; the pelvic-fin spine length is 4.6% SL; the pelvic-fin rays terminate distant from the anal-fin origin.
Dorsal fins—The D1 contains seven slender spines (Figs. 5e, 7g); spines I–V taper into short filaments; spine II is the longest (13% SL); spines I and III are slightly shorter (98.4% of spine II), while the subsequent spines decrease in length posteriorly (89%, 67%, 42% and 17% of spine II, respectively). The gap between spines V and VI is relatively long (4.6% SL) and 2.2 times greater than that between spines IV and V. The pterygiophores of the D1-spines IV and V are displaced, but the formula clearly begins with 2–1…. The D2 inserts opposite to the first caudal vertebra. It consists of a relatively thin, long (9.0% SL) and slightly curved spine (whether it tapers into filaments is not clear) and 14 segmented and branched rays. The D2-rays are incomplete posteriorly; perhaps they become progressively longer posteriorly, as some of the posterior rays seem to reach the first procurrent caudal rays.
Anal fin—The anal fin inserts below the third caudal vertebra, i.e., two vertebrae behind the origin of D2. It comprises a moderately long, thin spine (4.9% SL) and 13 rays; most of the rays have about the same length and it is not clear whether their distal ends extend to the caudal-fin origin. The pterygiophores of the anal-fin spine and anterior rays are not recognizable.
Caudal endoskeleton and fin—Only the proximal portion of the caudal fin is preserved; therefore, its shape cannot be determined. Based on its preservation, it is unclear if the caudal fin contains 17 principal rays (with eight rays in the lower lobe) or 16 principal rays (assuming the uppermost ray split longitudinally post-mortem). Seven and six procurrent rays are present dorsally and ventrally, respectively; some of them display their forked bases. The caudal skeleton comprises two large hypural plates (HY1 + 2 and HY3 + 4), of which the upper is fused with the terminal centrum (Fig. 8e); hypural 5 is about half the length of HY3 + 4 and thin. The epural is slightly curved, elongate and relatively large; the parhypural is relatively long, narrow and closely associated with the widened haemal spine of the second preural vertebra (PU2); the neural spine of PU 2 seems to be short.
Otoliths—The holotype of this species retained both sagittae in situ, but no lapilli. There is a notable asymmetry between the right and left sagittae, as described below. For measurements see Table 1, for the described characters see Fig. 9i, j.
Sagitta: Inner (= medial) face flat; outer (= lateral) face convex, with centrally located bulge accounting for about 50% of the sagitta height; general sagitta shape more or less squarish-to-rounded, with curved, weakly developed posterodorsal bulge (more prominent in the left sagitta) and small preventral projection; ventral portion of sagitta slightly wider than dorsal portion; dorsal margin regularly curved (left sagitta) or highest posteriorly and slightly indented in the middle (right sagitta); below the posterodorsal bulge is a V-shaped incision, followed by the curved ventral portion of the posterior margin; ventral margin slightly crenulated, almost straight in the middle, otherwise weakly curved; anterior margin faintly rounded (left sagitta) or with a few knobs (right sagitta); ventral line well developed; its anterior end almost reaches the ostium tip, its posterior end terminates distant from the cauda end; dorsal depression longish and shallow; sulcus of ‘shoe-sole’ shape and clearly inclined (α = 15.5–18.5°); ostium smoothly curved; cauda longish and terminally rounded; in the right sagitta the cauda is distinctly narrower than in the left sagitta; a thin crista superior and a thin crista inferior surround both the ostium and cauda; the crista inferior is especially well developed along the cauda.
Scales—Scales are relatively thin; scale cover is dense (Figs. 5e, 11e1). The flank scales are ctenoid and circular or ovate (Fig. 11e2–3); ctenii are short, number of radii appears to be seven. Scale number in longitudinal row is about 41. The predorsal and belly scales are smaller than the flank scales; whether ctenii are present is not clear. Thin scales also cover the base of the caudal-fin rays (Fig. 8e).