Taxonomy
Paradoxides sensu lato is a prime example of taxonomic problems that can result from the subdivision of a well-known, broadly defined genus into more tightly defined genera and/or subgenera based on locally distinctive species. Šnajdr’s (1957) subgenera are largely based on Bohemian species. In the present-day concepts of these genera or subgenera with numerous additional species included these type species lie distinctly eccentric in the morphological ranges so that these species are often not typical for the genera’s or subgenera’s morphology. Nomenclatural stability, however, requires definition of genera and subgenera of the Paradoxides s.l. clade by reference to Šnajdr’s and to subsequent genus definitions.
Based on the existing nomenclatural studies, Eccaparadoxides must be defined primarily on the basis of the morphology of Paradoxides pusillus Barrande, 1846. The diagnostic characters of this species feature the following: a fairly slender glabella (with respect to the maximum width of the cranidium); distinctly marked glabellar furrows S3 and S4; long, thin to moderately broad (tr.) and distinctly arcuate palpebral lobes extending into relatively transversely directed eye ridges; an anterior border with moderate curvature medially that extends into relatively weakly curved, slightly abaxially expanding lateral sectors; a facial suture intersecting the anterior border adaxial to the most abaxial position of the palpebral lobe’s centre; a pygidium with a subhexagonal outline, posterior margin slightly indented; axis with only one well-defined axial ring, length less than half of the pygidial length; pleural furrows absent.
Morphology
Given the morphological plasticity of the cranidial characters, particularly during ontogeny, few cephalic features allow discrimination of Eccaparadoxides from other taxa of the Paradoxides s.l. clade. Nevertheless, the length and curvature of the palpebral lobes and their continuation into the eye ridges; the relatively slender posterior of the glabella, the distinct glabellar furrows S3 and S4; and the adaxial position of the facial suture provide distinctive criteria for the cranidium of Eccaparadoxides. More readily recognisable is the pusillus-type pygidium with its elongated subhexagonal outline, a transverse posterior margin and a relatively short tapering axis with only one ring clearly marked. The same types of cranidia and pygidia are known from the coeval and partly co-occurring species E. rohanovicus, and, partly, from Mawddachites kozaki from Bohemia and E. zelus sp. nov. from the Delitzsch–Torgau–Doberlug Syncline, Germany, and E. epimetheus sp. nov. from the Anti-Atlas of Morocco. The Bohemian species oppanol is too incompletely known to be referred to Eccaparadoxides with certainty. These Perunican–West Gondwanan species must be regarded as the characteristic subclade of Eccaparadoxides.
The western Avalonian species Eccaparadoxides eteminicus, E. lamellatus and E. acadicus certainly represent species that form another “subclade” which is closely related to the Perunican–West Gondwanan species noted above. The western Avalonian species are primarily characterised by a lamellatus-type pygidium, which is slightly more elongate and has more closely spaced posterolateral corners than the pusillus-type pygidium.
Another morphological cluster of species is centred in Iberia and includes the Spanish species Eccaparadoxides sequeirosi and E. pradoanus and a species from Spain, Sardinia and the Montagne Noire commonly reported as E. mediterraneus (see remarks above), Other taxa include a species identified in Spain as E. acadicus and the Anatolian species E. remus. Although their cranidia frequently show a greater variation than that shown by the typical E. pusillus-type cephala, these E. pradoanus-type species/forms are primarily characterised by a distinctly more longitudinally elongate outline of the pygidium with a consequently shorter pygidial axis and a progressive tendency to develop a slender posterior with a pair of short spines rather than simple corners. Eccaparadoxides marginatus from Anatolia lacks posterolateral spines, but has a bilobate posterior margin of the elongate pygidium. It possibly is a precursor of the forked posterior margins typical for the pradoanus group.
Phylogeny
Both the lamellatus and the pradoanus groups appear to evolve into species in which the pygidia have a lateral margin with a double curvature, which means the posterior end is developed has a sort of swallow-tail outline. A pygidium showing this feature is figured from the “forchhammeri Grits” of Shropshire, eastern Avalonia (Cobbold and Pocock 1934: pl. 42, fig. 9), but without a known cranidium this specimen provides little evidence for phylogeny. Hence, it remains an open question whether the development of this type of pgidium records parallel or convergent evolution as suggested by species from different palaeocontinents or whether it originated in the Mediterranean sector of West Gondwana. The stratigraphic distribution of the species and differences in cranidial features between both groups seems to indicate separate evolutionary lineages.
The core group of species with a swallow-tailed pygidium include Eccaparadoxides/Macrocerca melaguesensis from the Montagne Noire and a form identified as E. melaguesensis from Spain, a species earlier identified as E. brachyrachis (sic) from the Montagne Noire and macrocercus from the Montagne Noire. The latter species is particularly striking because of its very elongated posterior part of the spatulate pygidium; it is the type species of the subgenus Macrocerca. Although this species was likely derived from a species with the E. melaguesensis morphology, E. macrocercus has a pygidial morphology and a facial suture that differ in such distinctive characters from those of E. pusillus that it cannot be assigned to Eccaparadoxides based on the commonly accepted diagnostic concept of the genus. Consequently, Macrocerca should be raised from a subgenus to the genus level.
Two other species with a violin-shaped pygidium with a double curvature of its outline and short, swallow-tail end should be mentioned. One is Eccaparadoxides freboldi from southeastern Newfoundland, which also has a similarly late, but probably only upper Drumian occurrence (see remarks above) as macrocercus. Eccaparadoxides freboldi, however, could be derived from an E. lamellatus-type species.
The second is a species/form from Bornholm represented by a similar pygidium with a swallow-tail posterior margin separated by curved lateral margins and an axis with at least two recognisable rings and ca. half the pygidial length. This species was erroneously described by Brøgger (1878) from the Oslo region, Norway and by Grönwall (1902) as “Paradoxides rugulosus” (see Dies Álvarez et al. 2010: figs. 2C, 2J). As emphasised by Dies Álvarez et al. (2010), the pygidia of this Scandinavian species/form closely resemble those of Eccaparadoxides mediterraneus as known from Spain, but their cranidia can be relatively easily distinguished.
Given the fact that the species from the lower Amgan of the Siberian Platform assigned to Eccaparadoxides are not true species of Eccaparadoxides, the oldest species of the genus are represented by two morphological groups. In Iberia, the species E. asturianus, E. sdzuyi and E. sulcatus are of Wuliuan age. All are characterised by a pygidium with a subcircular outline, an axis of slightly more than half the pygidial length and with a tendency to have more than one well-defined axial ring. The somewhat younger species E. rouvillei appears to belong as well to this clade. Specimens from the Iberian Chains and the Montagne Noire seem to show slight morphological differences, but these may be a result of imperfect preservation. In any case, the differences in pygidial and cranidial morphology with E. pusillus strongly suggest that these species cannot be assigned to Eccaparadoxides, and it is suggested to unite them as a new subgenus under Acadoparadoxides. Given the imperfect knowledge of E. asturianus, E. sdzuyi and E. sulcatus, we refrain from proposing this subgenus. Provisionally, this group is considered as an early plexus of Eccaparadoxides.
Species from the Wuliuan of Scandinavia with a pygidium with posteriorly expanding, subtriangular outline and spines on the posterior margin have been united by Šnajdr (1986) as the subgenus Baltoparadoxides under Acadoparadoxides—a reasonable proposal that appears to reflect the phylogenetic development in the region. These species would then include oelandicus, quadrimucronatus, and bidentatus. A possible additional species of Baltoparadoxides was described as P. immanis from coeval strata of the Olenek Uplift of the Siberian Platform.
The index species for the traditional lowermost “Middle Cambrian” in Scandinavia has been assigned to Eccaparadoxides as E.? insularis, which would make it the oldest known species of the genus globally. Its cranidium has relatively short anterior branches of the facial suture and fairly well defined lateral glabellar furrows S3 and S4, although not as deeply impressed as in typical species of Eccaparadoxides. The palpebral lobes, however, are more reminiscent of those in Acadoparadoxides. The pygidium has a short axis and a suboval outline with a slightly clipped posterior margin—more reminiscent to the pusillus-type species of Eccaparadoxides, but not typical for the genus. We therefore regard its generic assignment to Eccaparadoxides as provisional. Acadoparadoxides? pinus, the index fossil of the overlying biozone in Scandinavia, is not so different in its morphology and could be a morphologically distinct descendant of oelandicus. However, this species certainly cannot be assigned to Eccaparadoxides despite its short anterior branches of the facial suture. Another species from the pinus Biozone of Scandinavia was described as Eccaparadoxides? thorslundi (Rushton et al. 2016). Its morphology does not allow an unequivocal generic assignment, but it may be derived from an oelandicus-type ancestor and is a precursor of the pusillus-type plexus.
The genus Rejkocephalus Kordule, 1990, restricted to Bohemia/Perunica, is likely derived from species of the pusillus group. The genus includes two species, the type species R. rotundatus (Barrande, 1846) and R. knizeki Kordule, 1990, with a fairly different pygidial morphology. However, both are characterised by a similar cephalic morphology. The most striking features in the cranidium are the short palpebral lobes, which clearly differentiates them from the cranidia of Eccaparadoxides. The pygidial morphology is characterised by a broader overall shape and small, closely located posterior spines, which appears to indicate a simple morphologic/allometric gradient from E. pusillus-type predecessors. However, more important is the presence of several, posteriorly directed pleural ribs and additional axial rings. Specimens of Rejkocephalus knizeki appear to indicate the pathway for the addition of segments: incomplete fusion of axial rings in this species suggests that the morphology is generally a result of the fusion of the posterior thoracic segment with a E. pusillus-type pygidium (Fig. 5).
Systematic palaeontology
The specimens used for this study and listed below are in repository of the Bundesanstalt für Geowissenschaften und Rohstoffe, Außenstelle Geowissenschaftliche Sammlungen, Berlin-Spandau (GSB); the Mineralogisches Museum der Universität Würzburg (MMUW); the Národní Muzeum v Praze, Prague (NM); and the collection of Patrick Bommel (BOM).
Family Paradoxididae Emmrich, 1839
Subfamily Paradoxidinae Emmrich, 1839
Genus Eccaparadoxides Šnajdr, 1957
Type species. Paradoxides pusillus Barrande, 1846, from the Jince Formation, Bohemia, Czech Republic.
Discussion. This report has discussed existing taxonomic problems of the genus Eccaparadoxides. As outlined above, a majority of the species partly or occasionally assigned to Eccaparadoxides have a questionable generic assignment. However, the remaining species reflect at least four different morphological groups, termed the pusillus, lamellatus, pradoanus and asturianus groups. The systematic significance of these groups is difficult to assess based on the available data. In this report they are tentatively assigned to Eccaparadoxides, although the asturianus and pradoanus groups appear to be better placed outside Eccaparadoxides.
Eccaparadoxides zelus sp. nov.
Figures 6, 7, 8, 9
pars 1928 Paradoxides pusillus—Picard: 26.
pars 1931 Paradoxides pusillus—Picard and Gothan: 135.
1944 Paradoxides pusillus Barr.—Schmidt: 357, pl. 23, fig. 13.
1944 Paradoxides rugulosus Corda—Schmidt: 358–360, pl. 21, figs. 21–26, pl. 22, fig. 1–10.
1957 Paradoxides aff. rugulosus Corda 1847—Sdzuy: 11–12, fig. 1.
Etymology. Named for the Greek Ζῆλος, literally “zeal”; in Greek mythology the personification of dedication, emulation, eager rivalry and jealousy.
Holotype. GSB X4717, cranidium (Fig. 6a) (Schmidt 1944: pl. 21, fig. 26a, 26b; with counterpart).
Type locality. Doberlug IV/1929 drill site, northwest of Kirchhain, Delitzsch–Torgau–Doberlug Syncline, Northern Saxony, Germany.
Type stratum. Delitzsch Formation, Badulesia tenera Zone, Wuliuan–Drumian boundary interval, Miaolingian Series. From 195 m depth in the core (see Geyer and Malinky 2019: fig. 2).
Paratypes. Incomplete cephalon under GSB X12995 (from uncertain depth); 60 cranidia under GSB X4712 (Schmidt 1944: pl. 21, fig. 21; uncertain depth), GSB X4713 (Schmidt 1944: pl. 21, fig. 22; uncertain depth), GSB X4714 (Schmidt 1944: pl. 21, fig. 23a, 23b; uncertain depth), GSB X4715 (Schmidt 1944: pl. 21, fig. 24; from 186 m), GSB X4716/1 (Schmidt 1944: pl. 21, fig. 25; uncertain depth), GSB X4716/2 (on the same piece as GSB X4716/1; uncertain depth), GSB X4718 (Schmidt 1944: pl. 22, fig. 1; from 184 m), GSB X4719 (Schmidt 1944: pl. 22, fig. 2; uncertain depth), GSB X4720 (Schmidt 1944: pl. 22, fig. 3; from 186 m), GSB X4757b (from 190 m), GSB X06239/7 (from 186 m), GSB X06246/2 (from 187 m), GSB X12948/2 (uncertain depth), GSB X12950 (uncertain depth), GSB X12951 (uncertain depth), GSB X12952/1 (uncertain depth), GSB X12952/2 (uncertain depth), GSB X12953/1 (uncertain depth), GSB X12954 (uncertain depth), GSB X12955 (uncertain depth), GSB X12956 (from 190 m), GSB X12958 (from 195 m), GSB X12960 (uncertain depth), GSB X12961/1 (uncertain depth), GSB X12962 (uncertain depth), GSB X12963 (from 195 m), GSB X12964 (from 178 m), GSB X12965 (from 195 m), GSB X12967 (from 179 m), GSB X12968 (from 185 m), GSB X12969 (uncertain depth), GSB X12970 (from 198 m), GSB X12971 (from 189 m), GSB X12972 (uncertain depth), GSB X12973 (from 197 m), GSB X12976 (from 196 m), GSB X12979/2 (from 179 m), GSB X12980/1 (from 186 m), GSB X12980/2 (from 186 m), GSB X12981/1 (uncertain depth), GSB X12981/2 (uncertain depth), GSB X12982/2 (from 195 m), GSB X12982/3 (from 195 m), GSB X12983 (uncertain depth), GSB X12986 (from 195 m), GSB X12987 (uncertain depth), GSB X12989 (from 186 m), GSB X12990 (external mould, uncertain depth), GSB X12999/1 (uncertain depth), GSB X12999/2 (uncertain depth), GSB X12999/3 (uncertain depth); cranidium with attached librigena under GSB X12961/2 (uncertain depth); two incomplete cephala with attached hypostome under GSB X12957 (uncertain depth) and GSB X12959 (from 194 m); three nearly complete dorsal exoskeletons under GSB X12948/1 (uncertain depth), GSB X12974 (from 197 m) and GSB X12979/1 (from 197 m); enrolled specimen with most of the thorax covered in the matrix, with ventral side of cephalon with attached rostral plate and hypostome as well as posterior part of the thorax and pygidium exposed, GSB X4721 (part and counterpart; Schmidt 1944: pl. 22, fig. 4; uncertain depth); cranidium with attached partial thorax under GSB X12999/4 (uncertain depth); incomplete, partly detached thoraces under GSB X4724 (Schmidt 1944: pl. 22, fig. 7; uncertain depth), GSB X12991 (from 186 m) and GSB X12994 (uncertain depth); incomplete thorax with articulated pygidium under GSB X06251/2 (uncertain depth), GSB X4722 (Schmidt 1944: pl. 22, fig. 5; from 194 m), GSB X12966 (uncertain depth); isolated thoracic segments under GSB X12982/1 (from 195 m), GSB X12992 (from 180 m) and GSB X12993 (from 184 m); five isolated librigenae under GSB X12947 (from 186 m), GSB X12991/2 (from 190 m), GSB X12982/4 (from 195 m), GSB X12982/5 (from 195 m), GSB X12984 (from 178 m); nine isolated hypostomata, GSB X4726 (Schmidt 1944: pl. 22, fig. 9a–c; from 195 m), GSB X4727 (Schmidt 1944: pl. 22, fig. 10a, 10b; from 195 m), GSB X12968 (from 197 m), GSB X12975 (from 186 m), GSB X12977 (uncertain depth), GSB X12978 (uncertain depth), GSB X12985 (uncertain depth), GSB X12997 (from 197 m), GSB X12998/2 (from 195 m); two pygidia with three thoracic segments attached, GSB X4723 (Schmidt 1944: pl. 22, fig. 6; from 186 m), GSB X4724 (Schmidt 1944: pl. 22, fig. 7; uncertain depth); three isolated pygidia under GSB X4725 (external mould; Schmidt 1944: pl. 22, fig. 8; from 190 m), GSB X12949/2 (from 189 m), GSB X12966/L (uncertain depth). All specimens from Doberlug IV/1929 core, northwest of Kirchhain, Delitzsch–Torgau–Doberlug Syncline, northern Saxony, Germany, middle Cambrian. The specimens figured by Schmidt (1944) were originally in the collection of the Geologisches Landesmuseum of the Reichsamt für Bodenforschung, Berlin, under Schmidt’s numbers or under provisional numbers. The specimens were transferred to the Zentrales Geologisches Probenarchiv of the German Democratic Republic and are now in the collections of the Bundesanstalt für Geowissenschaften und Rohstoffe, Außenstelle Geowissenschaftliche Sammlungen, in Berlin-Spandau (GSB) under the listed collection numbers.
Diagnosis. Species of Eccaparadoxides with glabella pyriform, posteriorly relatively slender, slightly expanding forward; frontal lobe subevenly rounded or with slightly less curved anterolateral margins; S3 distinct, slightly shallower than S4, terminates distant from axial furrow; S4 relatively short, distinctly incised, with funnel-shaped lateral termination in dorsal view; palpebral lobes strongly arcuate, anterior and posterior tips slightly thickened, posterior tips located roughly at level of occipital furrow, anterior tips at mid-L4 or slightly posterior to S4; eye-ridges with slight anterior curvature; anterior border moderately wide (sag. and exsag.), evenly curved around sagittal line, anterolateral parts almost straight, slightly expanding abaxially; anterior branches of facial suture intersect anterior border at most distal level of palpebral lobe or at level of palpebral furrow; pygidium with elongate subhexagonal outline, with rounded lateral corners or more or less evenly curved lateral margin, posterior median sector with distinct indentation; pygidial axis slightly more than half of pygidial length, with one fairly well-defined axial ring; lateral margin slightly raised at anterolateral corners, progressively weakly defined posteriorly; without recognisable pleural ribs. (Diagnosis for adult individuals.)
Description of adult morphology. Glabella moderately convex in transverse profile, ca. 92–95% cephalic length (including occipital ring), pyriform with slight anterior expansion in its posterior part. Four pairs of lateral glabellar furrows, S1 and S2 deeply incised and transglabellar, S3 and S4 less distinct but recognisable. S1 slightly posteriorly directed from near lateral margin of glabella and slightly curved. S2 transversely directed in its lateral portions, slightly posteriorly directed across the sagittal sector; S3 not continuous medially, its abaxial ends terminate well before the lateral margins of the glabella, faintly convex forward and slightly oblique to axis, generally slightly less distinct than S4; S4 fairly short and not continuous medially, well-incised on internal moulds, less so on the exterior of the cuticle, extend abaxially to the axial furrow often with a short funnel-shaped end (Fig. 6a, b), slightly oblique to the axis. Frontal lobe with anterior margin mostly with uniform curvature in dorsal view, but lateral sections sometimes with lower curvature; max. tr. width of anterior part of glabella lobe ca. 46–55% max. cranidial width across centre of palpebral lobes (ratio increases with sclerite size) and ca. 130–165% of width across occipital ring (generally decreasing with sclerite size). Occipital ring with gently curved posterior margin, but with low curvature medially across sag. line; max. sag. length ca. 16–20% cephalic length, width ca. 31–38% cranidial width across centre of palpebral lobes; with moderate sag. convexity and medial node located slightly posterior to the centre. Occipital furrow composed of a shallow median section which curves slightly forward and with distinct lateral sections almost normal to axis.
Palpebral lobe strongly arcuate, exsag. of ca. 42–49% max. cephalic length (generally slightly decreasing with increased size), well elevated, (sub)evenly convex in tr. section, its centre in adult individuals opposite middle part of L2 at axial furrow, anterior end of ocular suture opposite origin of S4 at axial furrow or faintly posterior to it, posterior end opposite anterior part of occipital ring; with nearly uniform width throughout except for slightly broadened posterior tips. Palpebral lobe confluent with eye ridge without distinct angulation, but with distinct change in direction. Eye ridge nearly straight or slightly sigmoidal, oriented oblique towards anterior from intersection with palpebral lobe, generally tapering and less convex in anterior half, fades at anterolateral corners of frontal lobe.
Intraocular genae ca. 19–23% max. cranidial width across centre of palpebral lobes and ca. 36–46% max. cephalic length (exsag.) adjacent to axial furrow; with slightly elevated, longitudinally oval bacculae in the posteroadaxial part.
Preglabellar field absent or in small specimens developed as very narrow strip confluent with anterior border furrow. Preocular areas irregularly triangular with low ridge parallel to the facial suture (arrow in Fig. 6b).
Anterior branches of facial suture straight, directed obliquely forward from anterior ends of ocular suture, curving distinctly adaxially from about posterior third of anterior border; abaxial tips of anterior border located approximately at exsag. level of centre of palpebral furrow. Posterior branches moderately long, directed steeply abaxially from posterior ends of palpebral lobes, adaxial part nearly straight, abaxial section with a slight curvature.
Anterior border elevated, central portion of anterior margin with moderate curvature, anterolateral parts of anterior margin nearly straight, posterior margin of anterior border more strongly posteriorly directed so that it expands slightly in exsag. width; surface with low convexity (sag., exsag.) (Fig. 6o, p).
Posterior border relatively narrow (exsag.), slight expansion in width toward facial suture, moderately elevated, almost straight or slightly sigmoidal in dorsal view. Posterior border furrow moderately deep on internal moulds, less impressed on exterior of cuticle, moderately broad throughout its course on cranidium.
Librigena with fairly narrow ocular platform. Lateral border moderately broad (tr.), subequal in width for most of its exsag. expansion, but widen posteriorly, moderately elevated in tr. profile and with nearly flat surface in its central (tr.) part, grades into a long, moderately thick, continuously and evenly tapering genal spine of gentle curvature, its base moderately wide, without a change in curvature of the lateral margin. Posterior border not entirely preserved in any of the available specimens, apparently narrow. Ventral doublure of lateral genal border and genal spine covered with coarse, roughly subparallel terrace ridges (Fig. 7b).
Rostral plate known from one exoskeleton, a simple plate with anterior and posterior margins running subparallel to each other and to the anterior cephalic border, with more pronounced curvature in sag. and exsag. profile; covered with fine, subparallel terrace ridges (Fig. 7b).
Hypostome with oval middle body and subrectangular posterior unit framed by lateral and posterior borders; sagittal length about two-thirds maximum width. Posterior border transverse medially; abaxially it trends obliquely laterally and anteriorly and curves into moderately long marginal spine projecting from lateral border and directed obliquely abaxially. Lateral border almost exsagittally directed.
Middle body a very convex anterior lobe of ca. 85% hypostomal length on sag. line; lateral parts of anterior lobe distinctly extended dorsally (Fig. 7i), covered by terrace lines more-or-less paralleling plate relief and forming longitudinally oval whorl. Posterior lobe of middle body semilunate, distinctly convex in sag. and exsag. profile, laterally separated from anterior body by distinct oblique furrows. Maculae not recognised.
Thorax known from three more-or-less complete specimens and several disarticulated segments. With at least 16 segments. Segments of generally similar shape, but successive posterior decrease in size, with decreasing pleural length (tr.), width of axial rings (tr.) and an increasing posterior orientation of pleural spines. Axial ring widest at segment 1 where it is slightly narrower than 30% width of entire segment, rings successively narrow to segment 16, to a width slightly less than half the width of axial ring of segment 1 and slightly less than 40% width of segment 16. Axial rings with nearly straight anterior and slightly concave posterior margin and slightly constricted medially. Lateral portions with faint swellings near axial furrows, indicating attachment sites of ventral muscles. Articulating half-ring moderately wide (sag., exsag.).
Thoracic pleurae divided by a moderately deep, well-developed pleural furrow which starts adaxially near anterolateral corners of axial ring and runs slightly oblique to axis to end at approximately two-thirds the exsag. width in adaxial third of the pleural spines. Boundary between pleural spine and adaxial part of pleura marked by minute triangular fulcral process at anterior margin and corresponding notch-like indentation at posterior margin (Fig. 9n). Pleural spines elongate, moderately posteriorly curved in anterior half of thorax. Pleural spine progressively lengthens relative to segment size and curves posteriorly and broadens in segments ca. 9–16. Posterior segments 14–16 have blade-like, overlapping pleural spines that frame the pygidium laterally (e.g., Fig. 7c, e). Tips of pleural spines in segment 16 approximately at the level of the posterior pygidial tips.
Pygidium longitudinally suboval, maximum transverse width near midlength, ca. 80–85% sagittal pygidial width; lateral margin nearly uniformly curved in anterior two-thirds, slightly less curved in the posterior third. Posterior margin moderately wide (tr.), slightly concave in dorsal view. Axis subtriangular in outline, with rounded posterior margin, rests on indistinctly defined socle, axis of slightly more than half the pygidial length; only one axial ring distinctly defined by straight furrow, remaining part of axis with indistinct, shallow median impression at about midlength; with well-defined, narrow (sag.) articulating half-ring. Pleural fields apparently smooth, with low longitudinally directed ridge near axis in anterior sector. No pygidial border and border furrow developed for most part, but border developed as a low, poorly defined lobe anterolaterally. Ventral doublure of pygidium very broad, covered with relatively coarse terrace ridges.
Exterior of cuticle either smooth or covered with minute granules. Anterior border and lateral cephalic border with terrace ridges parallel to the anterior, lateral and posterior margins.
Discussion. Eccaparadoxides zelus sp. nov. is closely related to E. pusillus, the type species of the genus. Single cranidia of the two species with similar preservation cannot be distinguished with any certainty although minor differences exist in the tendency of E. zelus to have weakly expanded anterior and posterior tips of the palpebral lobes and curved eye ridges. The frontal glabellar lobe in E. zelus sp. Nov. is fairly slender, i.e. it has a low ratio of sag. length vs. max. tr. width at S4. This ratio is lower than in most other similar species (e.g., E. pusillus, E. rohanovicus or E. epimetheus sp. nov.).
The pygidium differs from that of Eccaparadoxides pusillus. It has an elongate subhexagonal outline with usually almost uniformly curved lateral margins or faint, rounded lateral corners, and the posterior median sector shows a distinct indentation. In addition, the pygidial axis is usually slightly more than half the pygidial length. The pygidium of E. pusillus, in contrast, has fairly well-marked lateral corners and a shallow indentation of the posterior margin; its axis is clearly shorter than half the pygidial length. The pygidium of E. rohanovicus has rounded lateral corners or curved lateral margins as in E. zelus sp. nov., but the posterior margin is almost straight, and its axis is also clearly shorter than half the pygidial length.
Remarks. Three specimens in the material are articulated, enrolled exoskeletons and thoraxes with attached pygidia. This suggest that the enrolled condition frequently occurred among the specimens embedded as entire and semicomplete individuals and that these animals were enrolled and rapidly buried alive by sediment. The mode of enrolment is comparable to that reported from other paradoxidine species (e.g., Esteve 2013; Geyer and Vincent 2015; Laibl et al. 2016). Loose enrolment includes specimens in which the thorax is slightly convex in lateral aspect, with the segments only slightly inclined against each other but with a stronger inclination in the posterior third of the thorax. The pygidium forms an inclined flap together with the three posterior segments (Fig. 7b, c, d); these segments and the pygidium then acted as a structural unit. Eccaparadoxides zelus sp. nov. was probably also capable of tight enrolment, as known in E. pradoanus (e.g., Esteve 2013: fig. 8E), with the pygidium resting below the cephalon. One specimen from the Doberlug IV drillhole (Fig. 7a, b) shows nearly complete, tight enrolment with the posterior thorax and pygidium underneath the anterior part of the thorax, whereas the cephalon lies slightly anterior to it.
Eccaparadoxides epimetheus sp. nov.
Figures 10, 11
1985 Paradoxides (Eccaparadoxides) sp.—Destombes et al.: 167.
2006 Paradoxides (Eccaparadoxides) sp.—Geyer and Landing: 107.
Etymology. Named for the Greek Titan Ἐπιμηθεύς, “hindsight”, or literally “afterthinker”; in Greek mythology the brother of Prometheus and the son of Iapetus.
Holotype. MMUW 2021-I-028, incomplete dorsal exoskeleton (Fig. 10h, k).
Type locality. Hassi Brahim section, north of the road from Tata to the Issafen area and 5 km WSW of Tata (Lambert coordinates 240/304, 29° 38′ 30″ N, 8° 22′ 30″ W), geological map sheet Akka–Tafagount–Tata 1: 200,000), southern flank of western Anti-Atlas, Morocco.
Type stratum. Level represented by sample HRG, Jbel Wawrmast Formation, Badulesia tenera Zone, Wuliuan–Drumian boundary interval, Miaolingian Series.
Paratypes. Incomplete cephalon under GSB X12995 (from uncertain depth); 60 cranidia. All specimens from Hassi Brahim area, mostly from the Hassi Brahim section (HBR-, with most sample horizons given in metres above base of measured section), southern margin of western Anti-Atlas. From sample HBR-D1887 (ca. 290 m above the base): incomplete dorsal exoskeleton under MMUW 2021-I-013; nine cranidia (often incomplete) under MMUW 2021-I-002, -003, -004, -006, -008, -010, -011, -012 and -014; fragmentary cephalon under MMUW 2021-I-005; hypostome under MMUW 2021-I-001; pygidium under MMUW 2021-I-007. From sample HBR-250.5: single cranidium under MMUW 2021-I-015. From sample HBR-316.5: cranidium under MMUW 2021-I-018; two hypostomata under MMUW 2021-I-016 and -017. From section slightly lateral of the HBR main section, sample HRG: three cranidia under MMUW 2021-I-026, -027, -029, two hypostomata under MMUW 2021-I-025 and -030. From sample HRG-A: five cranidia under MMUW 2021-I-019, -021, -032, -033 and -035, hypostome under MMUW 2021-I-020. From sample HRG-B: hypostome under MMUW 2021-I-0222. From sample HRG-F: cranidium under MMUW 2021-I-023; pygidium under MMUW 2021-I-024. From sample HRG-U: two cranidia under MMUW 2021-I-031 and -032.
Diagnosis. Species of Eccaparadoxides with pyriform glabella, posterior part moderately slender, slightly expanding forward; frontal lobe almost uniformly rounded or with slightly less curved anterolateral margins; S3 well-marked, terminates distant from axial furrow; S4 relatively short, but distinctly incised, with funnel-shaped lateral termination in dorsal view; palpebral lobes strongly arcuate, nearly uniform in tr. width, posterior tips located roughly at level of occipital furrow, anterior tips at mid-L4 or S4; eye-ridges straight, slightly oblique to axis; anterior border thin to moderately wide (sag. and exsag.), uniformly curved around sag. line, anterolateral portions almost straight, slightly expanding abaxially; anterior branches of facial suture intersect anterior border at level of centre of palpebral lobe or at level of palpebral furrow; pygidium with roughly subovate outline, posterolateral angles moderately rounded, posterior median sector with low curvature, without posterolateral corners; pygidial axis subtriangular, more than half the pygidial length, with one fairly well-defined axial ring; lateral margin slightly raised at anterolateral corners, progressively poorly defined posteriorly; one or sometimes two steeply posteriorly directed, low pleural ribs developed adjacent to anterior half of axis. (Diagnosis for adult individuals.)
Description of adult morphology. Glabella moderately convex in tr. profile, 92–95% cephalic length (including occipital ring), pyriform, slightly expanding forward in posterior part. Four pairs of lateral glabellar furrows, S1 and S2 deeply incised and transglabellar, S3 and S4 less distinctive but well-defined. S1 slightly posteriorly directed from lateral margins of glabella and slightly curved. S2 transversely directed laterally, with a slight posterior curvature across central part; S3 interrupted medially, its abaxial ends terminate distant to lateral margins of the glabella, weakly convex forward and slightly oblique to axis, generally slightly less distinct than S4; S4 fairly short and broadly interrupted medially, extends abaxially to axial furrow and sometimes with a short funnel shape in dorsal view (Fig. 10b, m), slightly oblique to axis. Frontal lobe with outline of a segment of a circle, anterior margin mostly with uniform curvature in dorsal view, lateral sections sometimes with lower curvature; max. tr. width of anterior part of glabella ca. 48–55% max. cranidial width across centre of palpebral lobes (increases with sclerite size) and ca. 135–160% width across occipital ring. Occipital ring with gently curved posterior margin, with low curvature medially across sag. line; max. sag. length ca. 13–18% cephalic length, width ca. 30–37% cranidial width across centre of palpebral lobes; with moderate sag. convexity and with median node. Occipital furrow composed of shallow median section, which curves slightly forward and with distinctive lateral sections almost normal to axis.
Palpebral lobe arcuate, exsag. ca. 42–54% max. cephalic length (generally slightly lower in large sclerites), distinctly elevated, almost uniformly convex in tr. section, but occasionally divided into two lobes by a faint subcentral depression (Fig. 10k); centre in adult individuals opposite S1 or middle of L2 at axial furrow, anterior end of ocular suture opposite origin of S4 at axial furrow or slightly posterior to it, posterior end opposite anterior part of occipital ring or occipital furrow, posterior ends always slightly more distant from axis than anterior ends; with nearly uniform width throughout except for slightly broadened posterior tips. Palpebral lobe confluent with eye ridge without distinct angulation to it, but with distinct change in direction. Eye ridge nearly straight or with slightly sigmoidal, directed obliquely anteriorly from its connection with palpebral lobe, generally tapering and less convex in its anterior half, fading at anterolateral corners of frontal lobe.
Intraocular genae ca. 20–24% max. cranidial width across centre of palpebral lobes and ca. 36–43% max. cephalic length (exsag.) adjacent to axial furrow; with distinct, slightly elevated, longitudinally oval bacculae in the posteroadaxial part.
Preglabellar field absent or developed as a very narrow strip confluent with anterior border furrow in small specimens. Preocular areas irregularly subtrapezoidal, with a low ridge parallel to facial suture.
Anterior branches of facial suture directed obliquely anterolaterally from origin at anterior ends of ocular suture, with straight section up to distinct adaxial curve at about posterior third of anterior border; abaxial tips of anterior border located approximately opposite the max. abaxial location of palpebral furrow or opposite adaxial half of palpebral lobes. Posterior branches short to moderately long, directed steeply abaxially from posterior ends of palpebral lobes.
Anterior border elevated, with moderate curvature of anterior margin in central sector, anterolateral parts of anterior margin nearly straight, posterior margin of anterior border more strongly posteriorly directed so that it widens slightly exsag.; surface with low convexity (sag., exsag.).
Posterior border relatively narrow (exsag.), relatively uniform in exsag. width or slightly widens toward facial suture, moderately elevated, almost straight or slightly sigmoidal in dorsal view. Posterior border furrow moderately deep on internal moulds, moderately broad throughout its course on the cranidium.
Librigena with fairly narrow ocular platform. Lateral border moderately broad (tr.), relatively uniform in width, but slight increases in width posteriorly, grades into a long, moderately thick, evenly tapering, gently curved genal spine, its base moderately wide without a change in curvature of the lateral margin; tips of genal spines located ca. one-third of body length from posterior end. Posterior border fairly narrow. Ventral doublure of lateral genal border and genal spine covered with coarse, roughly subparallel terrace ridges.
Rostral plate unknown.
Hypostome with oval middle body and subrectangular posterior part framed by lateral and posterior borders; sag. length about two-thirds of the max. width. Posterior border is transverse medially, but indented; abaxially it trends obliquely abaxially and forward and curves into a moderately long marginal spine extending from the lateral border with variable curvature.
Middle body of hypostome consists of strongly convex anterior lobe with ca. 80–85% length of hypostome on sag. line; lateral parts of anterior lobe distinctly dorsally extended (in anatomical position), covered by terrace lines more-or-less parallel to hypostome relief (Fig. 11a). Posterior lobe of middle body semilunate, distinctly convex in sag. and exsag. profile, defined from the anterior body laterally by distinct oblique furrows. Maculae not recognised.
Thorax known from four more-or-less complete specimens and several disarticulated segments, consisting of at least 16 segments. Segments generally of comparable morphology, but with anterior to posterior decrease in overall size with a decrease in pleural length (tr.) relative to pleural width (exsag.), a drecrease in width of axial rings (tr.) and increasing posterior orientation of pleural spines. Axial ring widest at segment 1 where it is slightly more than one-quarter width of segment, rings successively narrow to segment 16 where ring has a tr. width of slightly less than half of the axial ring at segment 1 and ca. 40% tr. width of segment 16. Axial rings with nearly straight anterior margin, slightly concave posterior margin, and thus weakly constricted medially. Lateral parts near axial furrows faintly swollen, indicating attachment sites of ventrally located muscles. Articulating half-ring moderately wide (sag. and exsag.).
Thoracic pleurae divided by moderately deep, well-developed pleural furrow, which starts adaxially near anterolateral corners of axial ring and runs oblique to axis to end at slightly more than half exsag. width and in adaxial third of the pleural spines. Boundary of pleural spine and adaxial part of pleura marked by triangular fulcral process at anterior margin and corresponding notch-like indentation at posterior margin. Pleural spines more or less falcate, moderately posteriorly curved in anterior half of the thorax. Pleural spine progressively lengthens relative to segment size and curves posteriorly to develop into broader spines in segments ca. 11–16. Posterior segments 14–16 have blade-like, overlapping pleural spines that envelop the pygidium laterally. Tips of pleural spines in segment 16 approximately opposite posterior pygidial tips (Fig. 11i).
Pygidium longitudinally suboval, max. tr. width near midlength, ca. 80% sag. pygidial width; lateral margin nearly uniformly curved. Posterior margin moderately wide (tr.), slightly concave in dorsal view. Axis subtriangular in outline, with rounded posterior margin, rests on weakly defined socle, approximately half the pygidial length. One axial ring defined by straight, deep furrow, a second one faint; articulating half-ring well-defined, narrow (sag.). Pleural fields apparently smooth with low longitudinally directed ridge near axis in the anterior half (Fig. 11l, m), a second one sometimes faintly indicated (Fig. 11m). No pygidial border and border furrow developed for most part, but border developed as a low and weakly defined lobe anterolaterally. Ventral doublure of pygidium very broad, covered with relatively coarse terrace ridges (Fig. 11g, j, l, m).
Exterior of cuticle apparently smooth. Anterior border and lateral cephalic border with terrace ridges parallel to anterior, lateral and posterior margins; anterior portion of middle body of hypostome with Bertillon pattern.
Discussion. Eccaparadoxides epimetheus sp. nov. has a cranidium typical of Eccaparadoxides, with a glabella with slightly diverging lateral margins posteriorly, a relatively short frontal lobe and well-impressed lateral glabellar furrows S3 and S4, the latter with apparently funnel-shaped lateral ends in dorsal view. The palpebral lobes are strongly arcuate; the anterior border is relatively narrow (sag.), with a moderate curvature on the sag. line, extending into weakly expanding lateral branches towards the facial suture, and it has a relatively flat dorsal surface. These features are typical of species of Eccaparadoxides of the pusillus and lamellatus groups. Specific cranidial characters of E. epimetheus sp. nov. are the prominent palpebral lobes and the moderately broad (tr.), rather than slender, glabella.
The species is best recognised by its pygidial characters. The pygidium has a more-or-less subovate outline where the posterolateral angles are gently rounded so that the median sector of the posterior margin has a low convex curvature rather than a slight indentation as in almost all other species of the pusillus and lamellatus groups and in species assigned to Eccaparadoxides in general. One or sometimes two steeply posteriorly directed pleural ribs occur close to the anterior half of the axis, which is quite unusual for Eccaparadoxides species. A similar type of pygidial morphology is known from Mawddachites kozaki, from roughly coeval strata in Bohemia. The latter species is clearly differentiated from E. epimetheus sp. nov. in having a more subtrapezoidal outline of the pygidium and a shorter pygidial axis. Its cranidium has less elevated palpebral lobes. It has a peculiar anterior border, which is very narrow on the sagittal line and strongly bent backward, and forms distinctly curved anterolateral sections with concave sectors of the anterolateral margin. The subcircular to ovate pygidial outlines of the asturianus group resemble that of E. epimetheus, but this is a superficial similarity. The course of the anterolateral margin in the asturianus group species is always oblique abaxially, whereas the axis tends to be shorter and more strongly tapering, subtriangular. In addition, the palpebral lobes are less arcuate and the anterior cephalic border tends to be broader and more uniformly curved.
Eccaparadoxides? hestia sp. nov.
Figures 12, 13
Derivation of name. Name after Hestia (Ἑστία), an ancient Greek goddess associated with then-traditional virtues, including modesty; the name is an allusion to the relatively modest size and morphologically subtle features of sclerites of the species.
Holotype. MMUW 2021-I-036, dorsal exoskeleton, preserved as part and counterpart (Fig. 12).
Type locality. Lemdad Syncline, section Le V, High Atlas, Morocco, 30° 48′ 20″ N, 8° 14′ 45″ W.
Type stratum. Jbel Wawrmast Formation, Kymataspis arenosa Zone, upper Agdzian/Wuliuan, Miaolingian Series/Middle Cambrian (see Geyer et al. 1995: figs. 11, 14).
Paratypes. All specimens from Jbel Wawrmast Formation, Kymataspis arenosa Zone, Lemdad Syncline, western High Atlas, Morocco. From section Le I, sample horizon 1–7 (7 m above base of the measured section): MMUW 2021-I-056 (exoskeleton, mould of ventral side with hypostome), -048, -057 (two cranidia), -055 (hypostome); sample 1–9 (9 m above base of the measured section): MMUW 2021-I-060 (enrolled specimen, ventral side), -061 (incomplete dorsal carapace), -062 (cranidium), -059 (thoracic pleura); samples 1–12 (12 m above base of the measured section): MMUW 2021-I-058; samples 1–12.5 (12.5 m above base of the measured section): MMUW 2021-I-065, -066 (pygidia); from section Le IV, samples 1–10 (10 m above base of the measured section): MMUW 2021-I-050 (hypostome with rostrum); section Le VIII, sample 1: MMUW 2021-I-051 (partial dorsal exoskeleton); from section Le XI, sample 1-north: MMUW 2021-I-052 (cranidium); section Le XV, sample 1–25 (ca. 25 m above base of the measured section): MMUW 2021-I-043, -044 (two cranidia), samples 1–30 (ca. 30 m above base of the measured section): MMUW 2021-I-042 (single cranidium), sample 1-st: MMUW 2021-I-045 (incomplete dorsal carapace), -046 (cranidium); section Le XVI, samples 1–11: MMUW 2021-I-047 (cranidium); locality X61: MMUW 2021-I-037, -038 (two cranidia); locality X64: MMUW 2021-I-039 (incomplete dorsal exoskeleton); locality X76: MMUW 2021-I-040 (incomplete cranidium); locality X203: MMUW 2021-I-041 (incomplete cranidium). See Geyer et al. 1995: figs. 11, 14 and Geyer and Landing 2006: fig. 23 and 28 for logs and sample locations.
Material in repository tentatively assigned to Eccaparadoxides? hestia sp. nov. All specimens from, Jbel Wawrmast Formation, Kymataspis arenosa Zone, Lemdad Syncline, western High Atlas, Morocco. From section Le I, sample horizon 1–12.5: MMUW 2021-I-063 and -064 (two pygidia), from section Le IV, sample horizon 1–7: MMUW-I-049 (cranidium).
Diagnosis. Species tentatively assigned to Eccaparadoxides with pyriform glabella, posterior part relatively broad, slightly expands anteriorly; frontal lobe with uniformly curved anterior margin; S3 and S4 moderately deep; palpebral lobes moderately arcuate, relatively thick (tr.) on the exterior of the cuticle, posterior tips opposite occipital furrow, anterior tips opposite S4 or slightly posterior to it; eye ridges almost transverse; anterior border moderately wide (sag. and exsag.), evenly curved around sagittal line, anterolaterally gently curved to almost straight, slightly expanding abaxially; anterior branches of facial suture intersect anterior border at level of centre of palpebral lobe; pygidium with elongate subovate outline, lateral margins with relatively low curvature, posterior median sector almost straight; pygidial axis slightly more than half pygidial length, posterior margin uniformly curved; without recognisable pleural ribs.
Description of adult morphology. Glabella moderately convex in tr.nsverse profile, ca. 87–93% cephalic length (including occipital ring), pyriform, slightly anteriorly expanding in posterior part. Four pairs of lateral glabellar furrows, S1 and S2 well-developed and transglabellar, S3 and S4 less distinctive, often weakly developed. S1 slightly posteriorly directed near lateral margins of glabella and curved to mostly form a uniformly curved arc. S2 transversely directed laterally, with a slight posterior curvature across centre of glabella; S3 fades medially, its abaxial ends terminate well before lateral margins of glabella, oriented slightly oblique to axis; S4 fairly short and broadly interrupted medially, extends abaxially to or near to axial furrow, slightly oblique to axis. Frontal lobe with r anterior curvature, outline almost semicircular, anterior margin mostly with uniform curvature in dorsal view. Max. tr. width of anterior part of glabellar lobe ca. 50% of max. cranidial width across centre of palpebral lobes and ca. 135% (130–145%) tr. width of occipital ring. Occipital ring with gently curved posterior margin; max. sag. length ca. 13–16% cephalic length, width ca. 30–35% of cranidial width across centre of palpebral lobes; with moderate sag. convexity and with median node. Occipital furrow with shallow median section which curves slightly forward and distinctive lateral sections almost normal to axis.
Palpebral lobes arcuate, exsag. ca. 45–52% max. of cephalic length (ratio slightly decreasing with growing sclerite size), moderately elevated, mostly uniformly convex in tr. section; centre in adult individuals opposite middle part of L2 to S2 at axial furrow, anterior end of ocular suture opposite origin of S4 or slightly posterior to it at axial furrow, posterior end opposite occipital furrow, posterior ends always slightly to distinctly more abaxial than anterior ends; comparatively broad (tr.), ca. 9–11% of max. cranidial width on exterior of cuticle, narrower (tr.) on internal moulds. Palpebral lobe confluent with eye ridge without distinct angulation. Eye ridge nearly straight, directed only slightly obliquely to axis but sometimes curves anteriorly, clearly tapers toward axial furrow and fades, extends into facial lines on preocular areas.
Intraocular genae ca. 19–25% of max. cranidial width across centre of palpebral lobes and ca. 40–45% of max. cephalic length (exsag.) adjacent to axial furrow; with slightly elevated oval bacculae in the posteroadaxial sector (e.g., Fig. 13a).
Preglabellar field absent. Preocular areas irregularly subtrapezoidal.
Anterior branches of facial suture directed obliquely anterolaterally from origin at anterior ends of ocular suture, form straight line that changes into an adaxial curve commencing at about the posterior third of the anterior border; abaxial tips of anterior border located approximately in front of the abaxial margin of palpebral furrow or in front of adaxial half of the palpebral lobe. Posterior branches short to moderately long, directed steeply abaxially from posterior ends of palpebral lobes.
Anterior border elevated, with moderate curvature of anterior margin in the central sector, anterolateral parts of anterior margin weakly curved, posterior margin of anterior border more strongly posteriorly directed so that it widens slightly in exsag. direction; surface with moderate sag. and exsag. convexity.
Posterior border relatively narrow (exsag.), subequal in exsag. breadth or slightly wider toward facial suture, moderately elevated, weakly sigmoid in dorsal view. Posterior border furrow moderately deep and broad throughout its course on the dorsal side of the cranidium.
Librigena with fairly narrow ocular platform. Lateral border moderately broad (tr.), slightly convex in tr. section, subequal in width for most of its exsag. expansion, slightly wider posteriorly, grades into a moderately long and moderately strong, uniformly tapering genal spine with gentle curvature, base relatively wide, without much change in curvature of lateral margin; posterior tips of genal spines opposite anterior half of thorax. Posterior border fairly narrow, lateral border and genal spine covered with roughly subparallel terrace ridges.
Rostral plate mirrors outline of cranidial anterior border, with moderate to pronounced curvature centrally, anterolateral margin weakly curved, posterior margin more strongly posteriorly directed so that it slightly widens exsag.; surface with moderate sag. and exsag. convexity.
Hypostome with oval middle body and subrectangular posterior part framed by lateral and posterior borders; sag. length about two-thirds of max. width. Posterior border transverse medially, with lateral sections directed obliquely laterally and anteriorly, extending into relatively long, variably curved marginal spine.
Middle body of hypostome with convex anterior lobe which measures ca. 80–85% of hypostomal length on sag. line; lateral parts of anterior lobe distinctly dorsally extended. Posterior lobe of middle body semilunate, distinctly convex in sag. and exsag. profile, separated from anterior body laterally by distinct oblique furrow. Maculae not recognised.
Thorax known from a few more-or-less complete specimens and several disarticulated segments, with up to 16 segments. Segments with relatively uniform morphology, show progressive anterior to posterior size decrease, combined with shorter pleural spine length (tr.), width of axial rings (tr.), and increasing rearward orientation of pleural spines. Axial ring widest at segment 2 where it is about one-third width of segment, successively narrows to segment 16, where it has a width of ca. 55% width of axial ring at segment 2 and ca. 55% width of entire segment 16. Axial rings with weak forward curvature anteriorly and slightly concave posterior margin, and thus slightly constricted medially. Lateral parts near axial furrows distinctly swollen, indicating attachment sites of ventral muscles. Articulating half-ring moderately wide (sag. and exsag.). Axial rings in segments 3–6 with more pronounced constriction, indicate possibility of dorsal inclination against each other and against segments 2 and 7 during enrolment so that the carapace may have been distinctly concave in lateral view with maximum flexure.
Thoracic pleurae divided by a moderately deep, spindle-shaped, well-developed pleural furrow which originates adaxially near anterolateral corners of axial ring and runs oblique to axis to end at slightly more than half exsag. width; abaxial termination of pleural furrows located ca. one quarter of pleural length (tr.) from pleural tips in anterior segments, at about one-third to half tr. pleural length in the middle part of the thorax, and in the adaxial half of the pleurae in posterior segments. Boundary between pleural spine and adaxial part of pleura marked by faint triangular fulcral process. Pleural spines long, more-or-less falcate, moderately posteriorly curved in anterior half of thorax. Pleural spines progressively longer in larger segments. They curve more strongly towards the posterior and are broader in segments ca. 10–16. Posterior segments 14–16 have blade-like, overlapping pleural spines that form fan-shaped structure together with pygidium, with pleurae broadest opposite distal end of pleural furrow (Fig. 13m). Tips of pleural spines in segment 16 posterior to posterior pygidial margin (Fig. 12c).
Pygidium longitudinally suboval in outline, maximum tr. width at about midlength. Posterior margin moderately wide (tr.), weakly curved to nearly straight in dorsal view, extends into lateral margin without angulation or spines. Axis subtriangular in outline, with rounded posterior margin, rests on low, indistinctly defined socle, slightly more than half of pygidial length; only one axial ring defined by a straight furrow. Pleural fields smooth, grade into a longitudinal, low raised area along lateral border in anterior half. No pygidial border or border furrow developed. Ventral doublure of pygidium very broad.
Exterior of cuticle largely smooth. Glabella occasionally with recognisable terrace lines, anterior border and lateral cephalic border with terrace ridges parallel to anterior, lateral and posterior margins.
Ontogeny. Immature cranidia of Eccaparadoxides? hestia sp. nov. differ from those of adult individuals in having a relatively narrower glabella with posteriorly somewhat more parallel lateral margins; distinctly broader (rel.) fixigenae; narrower and more distinctly arcuate palpebral lobes; and a more evenly curved anterior margin of the cranidium (Fig. 13e, f). A very small pygidium is tentatively assigned to E.? hestia and appears to indicate considerable allometric growth (Fig. 13g): It has a broadly subovate outline with weakly curved lateral margins developing into a convex curvature of the posterior margin. The axis is triangular and more than two-thirds of the pygidial length.
Discussion. Eccaparadoxides? hestia sp. nov. is a relatively distinctive paradoxidine trilobite with a general Eccaparadoxides-type morphology. It differs, however, in a number of characters so that a confident generic assignment is not possible. Eccaparadoxides-type characters include the course of the anterior branches of the facial suture and the long arcuate palpebral lobes with its anterior tips at S4. By contrast, the relatively broad glabella with faint lateral glabellar furrows S3 and S4 and the tr. width of the palpebral lobes differ considerably from the typical characters seen in the pusillus group. The thorax is fairly broad, with a fan-like aspect of the posterior third, similar to the thoraxes in species of Acadoparadoxides. The pygidium has a slender subovate outline with a nearly straight posterior margin, with its widest part at about half-length. The posterolateral “corners” are gently rounded.
Eccaparadoxides? hestia resembles the more-or-less coeval E.? sdzuyi from Spain. The taxonomic problems with the latter species have been discussed above. Although there is a general similarity in their pygidia as far as is known based on the the imperfect material from Spain, there are considerable differences in their cranidia, such as the narrower glabella with a shorter anterior part and narrower fixigenae in E.? sdzuyi.
In addition, Eccaparadoxides? hestia resembles immature specimens of Acadoparadoxides? pinus and E.? insularis. Both Scandinavian species are distinguished by narrower outlines of the pygidia, and the pygidial axis in A.? pinus is distinctly longer. In addition, A.? pinus has thoracic pleurae that do not extend as far laterally, and A.? pinus and E.? insularis differ in other characters of the cranidium, particularly in having shorter palpebral lobes in adult or nearly adult individuals (see Westergård 1936: pls. VI, VII).
Biostratigraphy. Eccaparadoxides? hestia sp. nov. ranges through the entire Kymataspis arenosa Biozone in the western Anti-Atlas and can be used as an auxiliary index fossil for this zone. It is even more abundant than K. arenosa, and is the most common trilobite of these strata and characteristic of the upper Agdzian (middle–upper Wuliuan) strata in the region. However, its sclerites are often difficult to assign confidently to the species. In addition, the species is unknown from coeval strata in the western, central and eastern Anti-Atlas, where K. arenosa occurs.