Two new species of deepwater flathead Bembras Cuvier, 1829 from the Andaman Sea, eastern Indian Ocean

Abstract

Two new species of Bembras Cuvier 1829, Bembras leslieknappi sp. nov. and Bembras andamanensis sp. nov., are described from single specimens collected from the Andaman Sea off Myanmar, eastern Indian Ocean, in 2015. The two new species are distinguished from each other and five known congeners by the numbers of anal-fin rays and pectoral-fin rays (15 and 20 in B. leslieknappi vs. 14 and 20–21 in B. andamanensis), forward-slanting body scale rows above the lateral line (80 vs. 74) and upper limb gill rakers (3 vs. 4), as well as by head (41.5 vs. 42.1% SL), snout (14.3 vs. 13.8% SL) and orbit (10.4 vs. 10.9% SL) proportions, and color of the second dorsal (dusky, with blackish spots only on first spine and bases of many soft rays vs. pale, with many scattered blackish spots), pectoral (with a blotch vs. without it) and caudal (both with a broad band) fins.

Introduction

In 2015, the EAF-Nansen Project of FAO, in cooperation with the Myanmar government, conducted a trawl survey from the R/V Dr. Fridtjof Nansen off the coast of Myanmar to obtain biological and environmental information for the study area, and identify local species diversity for the compilation of an FAO marine species identification guide for fishery purposes. During the survey, two specimens of Bembras Cuvier in Cuvier and Valenciennes 1829 were collected (Fig. 1), both being characterized by a long slender body; elongate head with scaled posterior dorsal surface, opercle, postorbital and cheek region; the anterior tip of the upper jaw slightly projecting beyond that of the lower jaw when mouth closed; the top and sides of the head with spines; teeth in bands on the jaws and palatine, in a V-shaped patch on the vomer; the second dorsal fin with a spine anteriorly; the anal fin lacking spines; the caudal fin slightly concave posteriorly; and the dorsal and lateral head and body surfaces orange or red. Detailed comparisons with the five known species of the genus, Bembras adenensis Imamura and Knapp 1997, Bembras japonica Cuvier in Cuvier and Valenciennes 1829, Bembras longipinnis Imamura and Knapp 1998, Bembras macrolepis Imamura in Imamura and Knapp 1998 and Bembras megacephala Imamura and Knapp 1998 (see Imamura and Knapp 1998), revealed that the two specimens each represented a new, undescribed species, bringing to seven the species of Bembras known to date. The two new species are described herein and a key to known species of Bembras provided.

Fig. 1
figure1

Map showing sampling localities of Bembras leslieknappi sp. nov. (1) and Bembras andamanensis sp. nov. (2)

Materials and methods

Counts and measurements generally followed Imamura and Knapp (1997). Measurements were made with calipers to the nearest 0.1 mm, being routinely taken from the left side. Gill rakers were counted on the right side. In addition to the number of pored scales in the lateral line, numbers of forward and backward-slanting body scale rows above the lateral line were counted (Fig. 2). Terminology of head spines follows Knapp (1986). Institutional acronyms are from Fricke and Eschmeyer (2018). Standard lengths and head lengths are abbreviated as SL and HL, respectively.

Fig. 2
figure2

Diagrammatic illustration showing backward and forward-slanting body scale rows above lateral line (BSR and FSR, respectively) in Bembras

Bembras leslieknappi sp. nov.

(Proposed new common English name: Leslie Knapp’s deepwater flathead) (Fig. 3; Tables 12)

Fig. 3
figure3

Dorsal (upper) and lateral (lower) views of a fresh specimen of Bembras leslieknappi sp. nov., SAIAB 203647, holotype, 195.0 mm SL, collected off Tanintharyi coast, Myanmar, Andaman Sea, Indian Ocean

Table 1 Counts and proportional measurements of two new species of Bembras
Table 2 Anal-fin and pectoral-fin ray counts in seven species of Bembras

Holotype. SAIAB 203647, 195.0 mm SL, male, off Tanintharyi coast, Myanmar, Andaman Sea, Indian Ocean (10°23.33’ N, 97°24.81’ E), 181–184 m, R/V Dr. Fridtjof Nansen, stn 172, bottom trawl, 28 May 2015, collected by P. N. Psomadakis.

Diagnosis. A new species of Bembras with 15 anal-fin rays, 20 pectoral-fin rays, 80 forward-slanting body scale rows above lateral line, 3 upper limb gill rakers, head length 41.5% SL, snout length 14.3% SL, orbit diameter 10.4% SL, second dorsal fin (except for basal area and ray tips) dusky, with small blackish spots only on first spine and bases of many soft rays, pectoral fin with a blackish blotch posterodorsally and caudal fin with a broad blackish band posteriorly.

Description. Counts and proportional measurements are shown in Table 1.

Body long, slender, mostly covered with ctenoid scales; some cycloid scales on isthmus, thorax, abdomen and around base of anal fin. Head large, length 2.4 in SL, posterior margin of opercle reaching beyond base of 4th spine of first dorsal fin; posterior dorsal surface, opercle, postorbital and cheek regions scaled. Snout slender, longer than orbit diameter, length 2.9 in HL. Iris lappet absent. Interorbit narrow, less than one-fifth of orbit diameter, 20.2 in HL. Dorsal and lateral surfaces of head with spines. Nasal with a small knob-like spine. Lachrymal with one forwardly-directed spine anteriorly, two backwardly-directed spines posteriorly. One preocular spine in front of eye. Lateral surface of head with a suborbital ridge armed with five (right) or six (left) spines. Supraorbital ridge roughly serrated, comprising seven (right) or eight (left) spines. One postocular spine present. Preopercle with five (right) or four (left) spines, uppermost longest, with (right) or without (left) a supplementary spine. Opercle with two strong spines and a ridge lacking serrations. Subopercle with a distinct spine posteriorly. Pterotic with two spines. Parietal with one spine. A spine present between posteriormost supraorbital and parietal spines on frontal. Posttemporal with strong spine posteriorly, bearing a single small spine laterally. Preorbital, supratemporal and supracleithrum lacking spines. Posterior margin of maxilla extending slightly beyond anterior margin of eye; upper jaw length 2.9 in HL. Anterior tip of upper jaw projecting slightly beyond that of lower jaw when mouth closed. Upper jaw with a broad band of conical teeth laterally, villiform teeth medially. Lower jaw with a narrow band of villiform teeth, except for anterior portion with small conical teeth. Palatine with a narrow band of small conical teeth. Vomer with a V-shaped patch of small conical teeth in a single row anteriorly, two rows posteriorly; teeth becoming larger posteriorly. Each lateral-line scale with an exterior opening posteroventrally. First dorsal fin originating well behind posterior margin of opercle. Very low fin membrane present between first and second dorsal fins. Origin of pectoral fin posterior to that of pelvic fin. Pectoral fin rounded posteriorly; its length 5.1 in SL. Pelvic fin short, not reaching anus, its length 5.8 in SL. Caudal fin slightly concave posteriorly, its length 5.0 in SL.

Color when fresh (based on photographs). Dorsal and lateral surfaces of head and body red, with small scattered blackish spots; ventral surface white. Caudal peduncle with a blackish band ventrally. First dorsal fin with blackish spots; membrane between second and third spines, and along anterior margin of fourth to sixth spines dusky; spines pale pink. Second dorsal fin, except for basal area and tips of rays, dusky; rays pale pink. Pectoral fin red dorsally and yellow ventrally; anterior half with blackish irregular bands; posterodorsal portion with a large blackish blotch; posteroventral portion with a blackish irregular band; blackish bands on pectoral fin tending to be continuous ventrally. Pelvic fin white basally, elsewhere pale pink. Caudal fin red, a broad blackish band posteriorly, base with small blackish spots.

Color in alcohol. Head and body pale brown, small blackish spots scattered dorsally and laterally. Ventral portion of caudal peduncle with a blackish band. First dorsal fin with blackish spots; anterior portion slightly dusky. Second dorsal fin, except for basal area and tips of rays, dusky, with three and one small blackish spots on first spine and bases of many soft rays, respectively. Anal fin pale; bases of fin membranes between rays and posterior margin blackish. Pectoral fin pale, anterior half with blackish bands, lower half dusky, posterodorsal portion with a blackish blotch. Pelvic fin pale. Caudal fin pale, upper margin black and a broad blackish band posteriorly; base of caudal fin with small blackish spots.

Etymology. Named in honor of the late Dr. Leslie W. Knapp, who contributed greatly to fish taxonomy, especially that of deepwater flatheads (Bembridae) and flatheads (Platycephalidae).

Bembras andamanensis sp. nov.

(Proposed new common English name: Andaman Sea deepwater flathead) (Fig. 4; Tables 12)

Fig. 4
figure4

Dorsal (upper) and lateral (lower) views of a fresh specimen of Bembras andamanensis sp. nov., SAIAB 203646, holotype, 182.9 mm SL, collected off Ayeyarwady Delta, Myanmar, Andaman Sea, Indian Ocean

Holotype. SAIAB 203646, 182.9 mm SL, female, off Ayeyarwady Delta, Myanmar, Andaman Sea, Indian Ocean (14°10.26’ N, 95°2.55’ E), 116 m, R/V Dr. Fridtjof Nansen, stn 81, bottom trawl, 12 May 2015, collected by P. N. Psomadakis.

Diagnosis. A new species of Bembras with 14 anal-fin rays, 20 or 21 pectoral-fin rays, 74 forward-slanting body scale rows above lateral line, 4 upper limb gill rakers, head length 42.1% SL, snout length 13.8% SL, orbit diameter 10.9% SL, second dorsal fin pale, with many scattered small blackish spots, posterodorsal portion of pectoral fin without a large blackish blotch and caudal fin with a broad blackish band posteriorly.

Description. Counts and proportional measurements are shown in Table 1.

Body long, slender, mostly covered with ctenoid scales; some cycloid scales on isthmus, thorax, abdomen and around base of anal fin. Head large, length 2.4 in SL, posterior margin of opercle reaching beyond base of 4th spine of first dorsal fin; posterior dorsal surface, opercle, postorbital and cheek regions scaled. Snout slender, longer than orbit diameter, length 3.0 in HL. Iris lappet absent. Interorbit narrow, less than one-fourth of orbit diameter, 17.9 in HL. Dorsal and lateral surfaces of head with spines. Lachrymal with one forwardly-directed spine anteriorly, two backwardly-directed spines posteriorly. One preocular spine in front of eye. Lateral surface of head with a suborbital ridge armed with six spines. Supraorbital ridge roughly serrated, comprising 10 spines. One postocular spine present. Preopercle with five (left) or six (right) spines; uppermost longest, without a supplementary spine. Opercle with two strong spines and a ridge lacking serrations. Subopercle with a distinct spine posteriorly. Pterotic with two spines. Parietal with one spine. A spine present (right side) or absent (left side) between posteriormost supraorbital and parietal spines on frontal. Posttemporal with strong spine posteriorly, bearing a single small spine laterally. Nasal, preorbital, frontal, supratemporal and supracleithrum lacking spines, but a ridge present on frontal. Posterior margin of maxilla extending beyond anterior margin of eye; upper jaw length 2.9 in HL. Anterior tip of upper jaw projecting slightly beyond that of lower jaw when mouth closed. Upper jaw with a broad tooth band of conical teeth laterally, villiform teeth medially. Lower jaw with a narrow band of villiform teeth, except for anterior portion with small conical teeth. Palatine with narrow band of small conical teeth. Vomer with a V-shaped patch of villiform teeth in a single row anteriorly, conical teeth in two rows posteriorly, those on lateral margin smaller; teeth becoming larger posteriorly. Each lateral-line scale with an exterior opening posteroventrally. First dorsal fin originating well behind posterior margin of opercle. Very low fin membrane present between first and second dorsal fins. Origin of pectoral fin posterior to that of pelvic fin. Pectoral fin rounded posteriorly; its length 5.4 in SL. Pelvic fin short, not reaching anus; its length 6.2 in SL. Caudal fin slightly concave posteriorly, its length 5.4 in SL.

Color when fresh (based on photographs). Dorsal and lateral surfaces of head and body orange, with small scattered blackish spots; ventral surface white. First and second dorsal fins with many small scattered blackish spots, but lacking dusky regions; rays pale pink. Pectoral fin orange, middle portion dusky, posterodorsal portion without a large blackish blotch. Caudal fin orange, a broad blackish band posteriorly, dorsal margin with small blackish spots.

Color in alcohol. Head and body pale brown, small scattered blackish spots. First and second dorsal fins pale with many small scattered blackish spots. Anal and pelvic fins pale. Pectoral fin pale, middle portion dusky, posterodorsal portion without a blackish blotch. Caudal fin pale, a broad blackish band posteriorly, dorsal margin with small blackish spots.

Etymology. Named for the Andaman Sea, the type locality of the new species.

Comparisons

Bembras leslieknappi sp. nov. and Bembras andamanensis sp. nov. are most similar to Bembras megacephala in having higher numbers of pectoral-fin rays, upper limb gill rakers and forward-slanting body scale rows above the lateral line, a larger head and snout, and smaller orbit [pectoral-fin rays 20, 20–21 and 19–20 (usually 20), gill rakers 3, 4 and 3–4, body scale rows 80, 74 and 77–84, head lengths 41.5, 42.1 and 38.2–41.2% SL, snout lengths 14.3, 13.8 and 12.9–14.0% SL, and orbit diameters 10.4, 10.9 and 9.7–11.1% SL in B. leslieknappi sp. nov., B. andamanensis sp. nov. and B. megacephala, respectively] (Figs. 57). However, both new species are easily separable from the latter in having a broad blackish band on the caudal fin (vs. several narrow irregular dark bands). Bembras andamanensis sp. nov. also differs from B. megacephala in having 14 anal-fin rays (vs. 15) (Table 2). Both new species can be separated from Bembras adenensis, Bembras japonica, Bembras longipinnis and Bembras macrolepis by their longer head and snout (head lengths 38.4–42.0, 34.1–37.6, 36.2–38.3 and 35.1–38.5% SL, and snout lengths 12.1–12.5, 11.2–13.3, 11.5–12.4 and 11.2–12.8% SL in the latter four species, respectively) (Figs. 56). They are also distinguishable from B. adenensis in having a smaller orbit (orbit diameter 11.8–13.2% SL in B. adenensis; Fig. 7), from B. japonica and B. longipinnis in having higher numbers of pectoral-fin rays and upper limb gill rakers, and a broad blackish band on the caudal fin [vs. pectoral-fin rays 16–18, usually 17 in B. japonica and 17–19, usually 18 in B. longipinnis, and upper limb gill rakers 1 or 2 and a large dark blotch on the caudal fin in both species) (Table 2), and from B. macrolepis in having a larger number of forward-slanting body scale rows above the lateral line (55–62 in B. macrolepis). Bembras andamanensis sp. nov. also differs from B. adenensis in lacking a blackish blotch on the posterodorsal portion of the pectoral fin (vs. blotch present in B. adenensis; see Knapp 1979), and B. leslieknappi sp. nov. from B. japonica and B. longipinnis in having 15 anal-fin rays (13–15, usually 14 in B. japonica and 13–14, usually 14 in B. longipinnis) (Table 2). Finally, B. leslieknappi sp. nov. is separable from B. andamanensis sp. nov. in having a blackish blotch on the posterodorsal portion of the pectoral fin and the second dorsal fin dusky, with small blackish spots only on the first spine and bases of many soft rays (vs. pectoral fin without a posterodorsal blotch and second dorsal fin pale, with many scattered small blackish spots in the latter). These characters are also absent in the other known species of Bembras [except for B. adenensis, which has a posterodorsal blotch on the pectoral fin. In addition, Knapp (1979) described B. adenensis as B. japonicus and stated that “both dorsal fins with a series of small brownish spots”. Imamura and Knapp (1997) described it as a new species, B. adenensis, and mentioned that “color patterns now are mostly faded”. However, they illustrated the holotype as having the first dorsal fin with scattered small spots (but second dorsal fin mostly faded). Thus, Knapp’s (1979) description of “a series of spots” and “scattered” in this study are considered to be consistent with each other]. In addition, pectoral-fin ray number is also useful to separate B. leslieknappi sp. nov. (15) and B. andamanensis sp. nov. (14) from each other because the number is quite stable in species of Bembras (see Table 2).

Fig. 5
figure5

Head length (% SL) versus standard length (mm) in seven species of Bembras. Red B. leslieknappi sp. nov., blue B. andamanensis sp. nov., orange B. adenensis, green B. japonica, sky blue B. macrolepis, yellow B. megacephala, violet B. longipinnis. H indicates holotypes

Fig. 6
figure6

Snout length (% HL) versus standard length (mm) in seven species of Bembras. Symbols as in Fig. 4

Fig. 7
figure7

Orbit diameter (% HL) versus standard length (mm) in seven species of Bembras. Symbols as in Fig. 4

Selected characters which distinguish the two new species from each other and other congeners are summarized in Table 3.

Table 3 Comparison of selected characters in seven species of Bembras

Key to seven species of Bembras

1a. Caudal fin with several irregular narrow dark bands or a large intense dark blotch on the lower lobe………2

1b. Caudal fin with a broad dark band posteriorly…4

2a. Anal-fin rays 15; gill rakers on upper gill arch usually 3 or 4 (northern and northwestern Australia and Indonesia)………………B. megacephala

2b. Anal-fin rays usually 14; gill rakers on upper gill arch 1 or 2………3

3a. Pectoral fin usually with 17 rays, shorter than caudal fin (southern Japan to South China Sea)…B. japonica

3b. Pectoral fin usually with 18 rays, longer than caudal fin (northern and northwestern Australia)...B. longipinnis

4a. Forward-slanting body scale rows above lateral line 62 or fewer (eastern Australia)………B. macrolepis

4b. Forward-slanting body scale rows above lateral line 70 or more………5

5a. Orbit diameter 11.8–13.2% SL (Gulf of Aden)………..............B. adenensis

5b. Orbit diameter < 11% SL………............6

6a. Second dorsal fin dusky, small blackish spots present only on first spine and bases of soft rays; blackish posterodorsal blotch on pectoral fin (Andaman Sea)…….B. leslieknappi sp. nov.

6b. Second dorsal fin pale, small blackish spots scattered on this fin; blackish posterodorsal blotch on pectoral fin absent (Andaman Sea)………B. andamanensis sp. nov.

Comparative material. A total of 82 specimens of Bembras, representing five known species, deposited at AMS, BMNH, CAS, CSIRO, FRLM, HUMZ, NTM, QM, UMMZ and ZMH, and listed in Imamura and Knapp (1998), were examined here.

References

  1. Cuvier G, Valenciennes A (1829) Histoire naturelle des poissons. Tome quatrième. Livre quatrième. Des acanthoptérygiens à joue cuirassée. FG Levrault, Paris

  2. Fricke R, Eschmeyer WN (2018) A guide to fish collections in the catalog of fish. Electronic version, updated 31 January 2018. http://researcharchive.calacademy.org/research/ichthyology/catalog/collections.asp. Accessed 14 February 2018

  3. Imamura H, Knapp LW (1997) New species of a deepwater flathead, Bembras adenensis from the western Indian Ocean (Scorpaeniformes: Bembridae). Ichthyol Res 44:9–13

  4. Imamura H, Knapp LW (1998) Review of the genus Bembras Cuvier, 1829 (Scorpaeniformes: Bembridae) with description of three new species collected from Australia and Indonesia. Ichthyol Res 45:165–178

  5. Knapp LW (1979) Fische des Indischen Ozeans. Ergebnisse der ichthyologischen Untersuchungen wahrend der Expedition des Forschungsschiffes ‘Meteor’ in den Indischen Ozean, Oktober1964 bis 1965. A. Systematischer Teil, 22. Scorpaeniformes (4). Meteor Forsch-Ergebnisse (Biol) 29:48–54

  6. Knapp LW (1986) Family No 155: Platycephalidae. In: Smith MM, Heemstra PC (eds) Smiths’ sea fishes. Macmillan, Johannesburg, pp 482–486

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Acknowledgements

The EAF-Nansen Project is acknowledged for providing us with the opportunity to work with material of Bembras collected during the R/V Dr. Fridtjof Nansen Myanmar survey. We are grateful also to Jens-Otto Krakstad and Oddgeir Alvheim (Institute of Marine Research, Norway), and the crew and personnel involved in the Myanmar Nansen survey. We are deeply indebted to J Paxton and M McGrouther (AMS), A-M Woolger (formerly BMNH), D Catania and T Iwamoto (CAS), PR Last and A Graham (CSIRO), S Kimura (FRLM), HK Larson and R Williams (formerly NTM), RJ McKay (formerly QM), J Williams (USNM), D Nelson (UMMZ) and H Wilkens (ZMH) for making specimens available, and to GS Hardy (Ngunguru, New Zealand) for English corrections. This study was partly supported by JSPS KAKENHI Grant Number 2544019603 and “Japan Society for the Promotion of Science (JSPS) Asian Core Program—Establishment of research and education network on coastal marine science in Southeast Asia” funded to the first author (HI).

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Correspondence to Hisashi Imamura.

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This article was registered in the Official Register of Zoological Nomenclature (ZooBank) as 513182C5-0EB0-438C-85AA-27338C25E156.

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Imamura, H., Psomadakis, P.N. & Thein, H. Two new species of deepwater flathead Bembras Cuvier, 1829 from the Andaman Sea, eastern Indian Ocean. Ichthyol Res 65, 488–495 (2018). https://doi.org/10.1007/s10228-018-0639-2

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Keywords

  • Bembras leslieknappi sp. nov.
  • Bembras andamanensis sp. nov.
  • Description
  • Bembridae
  • Myanmar