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Engyprosopon marquisensis, a new species of bothid flounder(Pleuronectiformes: Bothidae) from the Marquesas Islands(French Polynesia)
Kunio Amaoka1* and Bernard Séret2
1 Hokkaido University, 3-1-1 Minato-cho, Hakodate, Hokkaido 041-8611, Japan (e-mail: [email protected])2 Muséum national d’Histoire naturelle, Département Systématique et Evolution, USM Taxonomie et Collections, Case postale 26,43 rue Cuvier, 75231 Paris cédex 05, France (e-mail: [email protected])
Received: November 30, 2004 / Revised: July 28, 2005 / Accepted: August 2, 2005
Abstract A new bothid flounder, Engyprosopon marquisensis, is described from 11 specimens col-lected in deep waters (108–408 m) off the Marquesas Islands (French Polynesia) during the Frenchexploratory cruise MUSORSTOM 9 in 1997. Engyprosopon marquisensis is similar to E. bellonaensisfrom the Chesterfield Islands and Bellona Plateau in the Coral Sea and E. vanuatuensis from offVanuatsu Island, but is easily distinguished from E. bellonaensis by the following combination ofcharacters: narrow interorbital space in both sexes, small mouth, short caudal fin, large number ofvertebrae, and fewer gill rakers. It differs from E. vanuatuensis by many scales in the lateral line, smalleyes, short ocular-side upper jaw, and short blind-side lower jaw. Engyprosopon marquisensis is thedeepest occurring (408 m) species of the genus, and constitutes the second species of this genus with aneastern distribution.
Key words Engyprosopon marquisensis · New species · Bothidae · Marquesas Islands
0.1 mm with dial calipers. Figures were drawn from photo-graphs of the holotype; not all bony ridges on the scale weredrawn, but all grooves were drawn.
Engyprosopon marquisensis sp. nov.(Figs. 1–4; Tables 1, 2)
Holotype. MNHN 2000-4373, male, 62.2 mm standard length (SL),Hiva Oa, Marquesas Islands (French Polynesia), R.V. Alis, CruiseMUSORSTOM 9, Stn. DW 1234, 9°42¢ S, 139°05¢ E, 408 m depth, Warendredge, Aug. 31, 1997.
Paratypes. Nine specimens collected with holotype: MNHN 2004-2978, male, 47.0 mm SL; MNHN 2004-2879, male, 50.0 mm SL; MNHN2004-2980, male, 39.1 mm SL; MNHN 2004-2981, female, 46.8 mm SL;MNHN 2004-2982, female, 63.3 mm SL; MNHN 2004-2983, female,58.5 mm SL; HUMZ 190685, male, 51.1 mm SL; HUMZ 190686, male,41.5 mm SL; HUMZ 190687, female, 63.5 mm SL; and one specimen,MNHN 2000-4348, male, 64.9 mm SL, Hiva Oa, Marquesas Islands(French Polynesia), R.V. Alis, Cruise MUSORSTOM 9, Stn. DW 1235,9°41¢ S, 139°03¢ E, 108–285 m depth, Waren dredge, Aug. 31, 1997.
Diagnosis. A deep-water species of the genusEngyprosopon with the combination of the following char-acters: gill rakers on the first arch 2–3 + 12–14; vertebrae10 + 26–27; interorbital width comparatively narrow; ante-rior margin of head gently arched without distinct notch; nojet-black blotches on caudal fin.
Description. Data for holotype are given first, followedin parentheses by ranges for the paratypes and averages for
IchthyologicalResearch
©The Ichthyological Society of Japan 2005
Ichthyol Res (2005) 52: 373–378DOI 10.1007/s10228-005-0299-x
Bothid flounders of the genus Engyprosopon, character-ized by a highly branched caudal skeleton, ctenoid
scales with short spines, and appearance of secondary sexualcharacters (Amaoka, 1969; Amaoka et al., 1993), are small-sized marine fishes widely distributed in the Indo-Pacificregion. About 25 valid species of Engyprosopon are known(Norman, 1934; Amaoka et al., 1993).
In taxonomic reviews of the species of the genusEngyprosopon (Amaoka, 1969; Amaoka and Imamura,1990; Amaoka et al., 1993; Amaoka and Mihara, 1995;Amaoka and Séret, 2005), 11 specimens of an undescribedspecies were found in material collected during an explor-atory cruise off the Marquesas Islands conducted by theFrench research institute IRD (Institut de Recherche pourle Development, formerly ORSTOM) in 1997. This newspecies is herein described, and comments on its geographicand bathymetric distributions are provided.
Material and Methods
Specimens examined are deposited in the collections of theMuséum National d’Histoire Naturelle, Paris (MNHN) andGraduate School of Fisheries Sciences, Hokkaido Univer-sity (HUMZ). Counts and proportional measurements fol-low those of Hubbs and Lagler (1958) and Amaoka et al.(1993). Scale definition follows that of Roberts (1993). Cau-dal skeleton and number of vertebrae were examined fromradiographs. All measurements were made to the nearest
374 K. Amaoka and B. Séret
proportional data including that for the holotype. Countsand proportional measurements as percent of SL are shownin Table 1.
Head 3.44 in SL (3.42–3.74, 3.58); body depth 1.95 (1.89–2.09, 2.00). Snout 4.53 in head length (4.33–5.45, 4.77); uppereye diameter 2.92 (2.60–2.94, 2.80); lower eye diameter 2.78(2.60–2.90, 2.76); interorbital width 9.53 (8.67–27.3, 15.1) inmale, (14.4–17.1, 15.5) in female; ocular-side upper jaw 2.66(2.60–2.90, 2.77), 2.83, (2.68–3.64, 2.86) on blind side; ocular-side lower jaw 2.21 (2.00–2.25, 2.12), 2.03 (1.98–2.10, 2.03)on blind side; caudal peduncle depth 2.35 (2.22–2.60, 2.45);ocular-side pectoral fin 1.06 (0.94–1.13, 1.05) in male, (1.01–1.14, 1.06) in female; 2.18 (2.03–2.24, 2.16) on blind side;
ocular-side pelvic fin 2.29 (2.34–2.76, 2.52), 2.29 (2.36–2.85,2.51) on blind side; base of pelvic fin 2.83 (2.24–2.85, 2.63)on ocular side, 9.05 (7.26–13.00, 9.31) on blind side; length oflongest dorsal fin ray 1.81 (1.61–2.28, 1.96); length of longestanal fin ray 1.97 (1.88–2.28, 1.98); length of mid-caudal finray 1.19 (1.15–1.26, 1.20); curve width of lateral line 1.97(1.74–2.22, 1.89).
Body shallow ovate, deepest at middle of body, its depthabout equal to half length of body; dorsal and ventral con-tours gently arched. Caudal peduncle narrow, its depthabout 1/4 of body depth.
Head small, its length less than 30% of SL, upper profilegently arched without a distinct notch in front of upper
Table 1. Proportional measurements as percent of standard length (SL) and counts inEngyprosopon marquisensis sp. nov.
Specimens Holotype Paratypes MeanSL in mm M M = 6, F = 4
62.2 39.1–64.9 53.4
Morphometrics in % SLHead length 29.1 26.7–29.2 28.0Body depth 51.3 47.9–53.0 50.0Snout length 6.4 5.1–6.4 6.0Upper eye diameter 10.0 9.4–10.7 10.0Lower eye diameter 10.5 9.4–10.6 10.1Interorbital width (M) 3.1 1.0–3.2 2.1Interorbital width (F) 1.7–1.9 1.8Upper jaw length (O) 10.9 9.4–10.9 10.1Upper jaw length (B) 10.3 9.6–10.7 10.1Lower jaw length (O) 13.2 12.5–13.9 13.2Lower jaw length (B) 14.3 12.8–14.4 13.8Depth of caudal peduncle 12.4 10.7–12.4 11.4Pectoral fin length (O, M) 27.5 24.8–29.6 26.6Pectoral fin length (O, F) 25.6–27.1 26.6Pectoral fin length (B) 13.3 12.3–13.7 13.0Pelvic fin length (O) 12.7 9.9–11.8 11.2Pelvic fin length (B) 12.7 10.3–11.9 11.3Base length of pelvic fin (O) 10.3 9.6–12.3 10.7Base length of pelvic fin (B) 3.2 2.1–3.8 3.1Length of longest dorsal ray 16.1 12.8–17.4 14.4Length of longest anal ray 14.8 13.9–14.9 14.3Caudal fin length 24.4 21.2–23.7 23.1Curve width of lateral line 14.8 12.0–16.0 14.9
MeristicsDorsal fin rays 86 82–91 85.1Anal fin rays 64 61–66 63.9Pectoral fin rays (O) 12 12–13 12.2Pectoral fin rays (B) 10 9–10 9.6Pelvic fin rays (O) 6 6 6Pelvic fin rays (B) 6 6 6Caudal fin rays 3 + 11 + 3 = 17 3 + 11 + 3 = 17 17Scales in lateral line 53 49–53 51.4Gill rakers 2 + 12 2–3 + 12–14 2.82 + 13Vertebrae 10 + 26 10 + 26–27 10 + 26.1
Means include counts and measurements of the holotypeM, male; F, female; O, ocular side; B, blind side
New bothid flounder from Marquesas Islands 375
Fig. 1. Engyprosopon marquisensis sp. nov., holotype, MNHN 2000-4373, male, 62.2 mm SL, from Marquesas Islands. Bar 5 mm
Table 2. Comparison of discriminable characters of the proportional measurements and counts between Engyprosopon marquisensis and tworelated species, E. bellonaensis and E. vanuatuensis
Species E. marquisensis E. bellonaensis E. vanuatuensis
Sources This study Amaoka et al., 1993; Amaoka and Séret, 2005;this study this study
Specimens M = 7, F = 4 F = 4 M = 9, F = 6SL in mm 39.1–64.9 (53.5) 26.4–72.4 (51.0) 41.1–55.8 (48.6)
Morphometric in SLHead length 3.42–3.74 (3.58) 3.52–3.59 (3.57) 3.09–3.49 (3.31)a
Morphometrics in head lengthUpper eye diameter 2.60–2.94 (2.80) 2.59–2.86 (2.75) 2.29–2.55 (2.45)a
Lower eye diameter 2.60–2.90 (2.76) 2.50–2.86 (2.74) 2.20–2.55 (2.43)a
Interorbital width (M) 8.67–27.3 (15.1) — 4.90–11.64 (6.58)Interorbital width (F) 14.4–17.1 (15.5) 5.71–15.0 (8.54)a 10.71–25.2 (16.2)Upper jaw length (O) 2.60–2.90 (2.77) 2.41–2.78 (2.63) 2.33–2.63 (2.49)a
Upper jaw length (B) 2.68–3.64 (2.86) 2.38–2.78 (2.57) 2.20–2.62 (2.47)a
Lower jaw length (O) 2.00–2.25 (2.12) 1.92–2.04 (2.00)a 1.90–2.15 (1.99)Lower jaw length (B) 1.98–2.10 (2.03) 1.90–1.99 (1.94)a 1.79–1.99 (1.90)a
Pectoral fin length (O, M) 0.94–1.13 (1.05) — 0.50–0.99 (0.65)a
Pectoral fin length (O, F) 1.01–1.14 (1.06) 0.87–1.05 (0.95)a 0.94–1.01 (0.98)a
Caudal fin length 1.15–1.26 (1.20) 1.09–1.16 (1.13)a 1.18–1.46 (1.32)Meristics
Pectoral fin rays (O) 12–13 (12.2) 11–12 (11.8)a 11–13 (12.1)Scales in lateral line 49–53 (51.4) 50–52 (50.8) 43–47 (44.8)a
Gill rakers 2–3 + 12–14 (2.8 + 13.0) 1–5 + 14–15 (3 + 14.3)a 0–3 + 13–14 (0.73 + 13.6)Vertebrae 10 + 26–27 = 36–37 (36.1) 10 + 25 = 35 (35)a 10 + 25–26 = 35–36 (35.2)a
Means are shown in parenthesesa Discriminable characters from E. marquisensisM, male; F, female; O, ocular side; B, blind side; —, no data
376 K. Amaoka and B. Séret
Fig. 2. Engyprosopon marquisensis sp.nov. A, C Holotype, MNHN 2000-4373,male, 62.2 mm SL, from MarquesasIslands; B paratype, MNHN 2004-2982,female, 63.3 mm SL, from MarquesasIslands
margin of lower eye, slightly steeper in mature males thanfemales and young. Snout round, its length less than 65% ofeye diameter. An obtuse rostral spine on snout in male,absent in female. Eyes large, slightly shorter than ocular-side upper jaw length; upper eye close to head margin,shortest distance less than 1/4 of upper eye diameter. Noorbital spine on both sexes. Interorbital region deeply nar-row concave, becoming wider with growth, wider in malesthan in females and young (Fig. 3).
Mouth large, oblique; maxilla extending to verticalthrough anterior 1/4 of lower eye; anterior tip of upper jawprojecting beyond tip of lower jaw, when mouth closed.Teeth on upper jaw biserial, those in outer series larger andstronger, and more widely spaced than those in inner series,and becoming larger with some canine teeth anteriorly; an-terior canine teeth outside of mouth, when mouth closed;lower jaw teeth uniserial, nearly equal in size to outer lateralteeth of upper jaw. Gill rakers on first arch slender, not
New bothid flounder from Marquesas Islands 377
serrate, those of upper limb very small (Fig. 4B). Scales onocular side large, with short and peripheral ctenii (Fig. 4A),snout and both jaws on ocular side naked; cycloid scales onblind side. Pectoral fin on ocular side slightly prolonged inboth sexes, without sexually dimorphic differences in length.Pelvic fin with six rays, origin of ocular-side fin at tip ofisthmus; fifth ray of ocular-side fin opposite to first ray ofblind-side fin. Tip of isthmus near vertical line through
middle of lower eye. Caudal fin rays branched, except forthree uppermost and three lowermost rays.
Coloration in alcohol.—Ground color of ocular side uni-formly light brown; scattered with numerous small darkdots on body. Vertical fins with numerous small dots. Ocular-side pectoral fin with three dark crossbands, the middle onemost conspicuous (Figs. 1, 2A,B). Blind side in males dusky,except for anterior half of body (Fig. 2C); that of femalesuniformly light yellow.
Sexual dimorphism.—This species has remarkable sexualdimorphism in the interorbital width (Figs. 1–3), degree ofanterior curve of head profile, presence or absence of arostral spine, and presence or absence of pigmentation onthe blind side of the body (Fig. 2C).
Etymology. Named after the Marquesas Islands wherethe type specimens were collected.
Distribution. All specimens were collected between 108and 408 m depth, off the island of Hiva Oa, MarquesasIslands (French Polynesia).
Comparison. Engyprosopon marquisensis belongs tothe group of species including Engyprosopon vanuatuensisAmaoka and Séret, 2005, Engyprosopon bellonaensisAmaoka, Mihara, and Rivaton, 1993, Engyprosopon xystriasHubbs, 1915, and Engyprosopon hensleyi Amaoka andImamura, 1990, which are characterized by having morethan 12 gill rakers on the lower limb of the first gill arch andwithout serrated gill rakers (Hubbs, 1915; Amaoka, 1969;Amaoka and Imamura, 1990; Amaoka et al., 1993; Hensleyand Amaoka, 2001; Amaoka and Séret, 2005). It mostlyresembles E. vanuatuensis and E. bellonaensis in having2–3 + 12–14 gill rakers on the first arch (0–3 + 13–14 and1–5 + 14–15 in the latter) and no jet-black blotches onthe caudal fin. Engyprosopon marquisensis differs from E.vanuatuensis in having more scales in the lateral line (49–53vs. 43–47), smaller upper eye diameters (2.60–2.94 in headlength vs. 2.29–2.55), smaller lower eye diameter (2.60–2.90in head length vs. 2.20–2.55), and smaller ocular-side upperjaw (2.6–2.9 in head length, vs. 2.33–2.63), and smaller blind-side lower jaw (1.98–2.10 in head length vs. 1.79–1.99). Itdiffers from E. bellonaensis in having smaller ocular-sidelower jaw (2.00–2.25 in head length vs. 1.92–2.04), smallerblind-side lower jaw (1.98–2.10 in head length vs. 1.90–1.99),shorter caudal fin (1.15–1.26 in head length vs. 1.09–1.16),more pectoral fin rays on ocular side (12–13 vs. 11–12),fewer gill rakers (2–3 + 12–14 vs. 1–5 + 14–15), more verte-brae (36–37 vs. 35), narrower interorbital width (Fig. 3; Table2), a gently arched upper profile of head, and no distinctnotch in front of upper margin of lower eye. Engyprosoponmarquisensis is easily separable from E. xystrias and E.hensleyi by the absence of a pair of jet-black blotches on thecaudal fin (Hubbs, 1915; Amaoka et al., 1993; Amaoka andImamura, 1990).
Remarks. Engyprosopon rostratum Amaoka, Mihara,and Rivaton, 1993 was known as the deepest species of thegenus with a depth record of 300 m. Most species of thegenus occur in less than 200 m (Amaoka et al., 1993;Hensley and Amaoka, 2001). With its capture depth of408 m, E. marquisensis is now the deepest occurring mem-ber of the genus Engyprosopon.
Fig. 3. Sexual dimorphism of interorbital width in Engyprosoponmarquisensis sp. nov. and comparison with E. bellonaensis. �, holotype(male) of E. marquisensis; �, paratypes (males) of E. marquisensis;�, paratypes (females) of E. marquisensis; �, types (females) of E.bellonaensis
Fig. 4. A scale (A) and first gill arch (B) from ocular side inEngyprosopon marquisensis sp. nov. from the holotype, MNHN 2000-4373, male 62.2 mm SL. Bars 1 mm
378 K. Amaoka and B. Séret
Engyprosopon regani Hensley and Suzumoto, 1990 wasrecorded from the coast of Easter Island, and this record isthe easternmost boundary in the distribution of the genus(Hensley and Suzumoto, 1990). Engyprosopon marquisensiscollected from Marquesas Islands (near longitude 139°E), isnow the second species of the genus occurring in the east-ernmost parts of the geographic range for this species.
Comparative specimens examined. Engyprosopon bellonaensis:holotype, MNHN 1993-26; 3 paratypes MNHN 1993-27, MNHN 1993-143, HUMZ 124864. Engyprosopon vanuatuensis: holotype, MNHN2000-4346; 14 paratypes MNHN 2004-907, MNHN 2004-908, HUMZ188581, HUMZ 188582.
Acknowledgments We thank Keiichi Matsuura and Gento Shinohara(NSMT), Kazuhiro Nakaya, Mamoru Yabe, and Hisashi Imamura(HUMZ), Patrice Pruvost (MNHN), and staff of the Marine EcologicalInstitute for various assistance during this study. Tom Munroe of Sys-tematics Laboratory, NMFS/NOAA, is thanked for reading the manu-script and offering helpful comments. The first author received a grantfrom MNHN to examine flatfishes collected during the MUSORSTOMcruises.
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