Acropoma lecorneti Fourmanoir, 1988

Okamoto, Makoto & Motomura, Hiroyuki, 2017, Proceedings of the 23 rd Paediatric Rheumatology European Society Congress: part two, Cybium 41 (4), pp. 373-375 : 373-375

Acropoma lecorneti Fourmanoir, 1988

[New English name: Lecornet’s lanternbelly]

( Figs 1 -2)

Acropoma lecorneti Fourmanoir, 1988: 259 , fig. 1 and photo (original description, west coast of New Caledonia); Yamanoue and Toda, 2008: 199, figs 1-3 (off Okinawa I., Japan).

Diagnosis

A species of Acropoma is distinguished from its congeners by the following combination of characters: O-shaped luminous ground around anus ( Fig. 1B ); luminous-gland length 13.2-14.6; proximal radial of 1st anal-fin pterygiophore slender lacking trough or hollow; anus pale situated closer to pelvic-fin origin than to that

Meristic and morphometric methods follow Hubbs and Lagler (1958) and Okamoto (2014). The condition of the luminous gland and the sex of the specimen were established by dissection of the abdomen on the right side. The specimens examined in the present study are deposited in the Kagoshima University Museum, Kagoshima, Japan (KAUM); Muséum national d’Histoire naturelle, Paris (MNHN); and National Museum of Nature and Science, Tsukuba, Japan (NSMT).

Material examined

Acropoma lecorneti , MNHN-IC-2008- 1612, 141.9 mm SL, female, Santo 06 cruise, R / V Alis, st. At121, 15°38’42”S; 167°01’12”E, West of Malo Island , Vanuatu, western South Pacific, 275-290 m depth, 19 Oct. 2006 .

(1) Marine Fisheries Research and Development Center ( JAMARC), Fisheries Research Agency, 15F Queen’s Tower B,

2-3-3 Minatomirai, Nishi-ku, Yokohama, Kanagawa 220-6115, Japan.

(2) The Kagoshima University Museum, 1-21-30 Korimoto, Kagoshima 890-0065, Japan. [[e-mail]]

Present Yamanoue and Toda Fourmanoir study (2008) (1988)

Standard length 141.9 mm 221 mm 326 mm

Dorsal-fin rays VII-I-I, 10 VII-I-I, 10 VII-I-I, 10

Anal-fin rays III, 7 III, 7 III, 7

Pectoral-fin rays 15 15 15

Gill rakers (left/right) 27/21 15/14 21/14

Lateral line scales 48 49 48

Head length 37.4 37 34.4

Body depth 24.8 25 24.5

Body width at P1 base 14.1 15 15.0

Orbital diameter 11.6 7.9 9.5

Interorbital width 7.0 8.5 7.7

Snout length 12.0 12 9.5

Postorbital length 15.1 15 No data

Upper-jaw length 16.1 16 15.6

Lower-jaw length 19.9 22 No data

Pre-1 st dorsal-fin length 40.4 42 No data

Pre-2 nd dorsal-fin length 62.8 64.1* No data

Prepectoral-fin length 36.9 37 No data

Prepelvic-fin length 40.4 40 No data

Pre-anus length 49.1 47.5* No data Figure 2. – Collection localities of Acropoma lecorneti (present study = Preanal-fin length 70.5 71 No data star; previous studies = circles). Pelvic fin base to anus 9.3 9.1 7.4

1 st dorsal-fin spine length 6.4 6.6 6.4

2 nd dorsal-fin spine length 12.0 13.6* 12 of anal fin; gill rakers 14-27; scales ctenoid except for axil of 3rd dorsal-fin spine length Broken 17 14 pectoral fin and cheek (cycloid). 7th dorsal-fin spine length 5.5 6.1 6.1

2 nd dorsal-fin spine length 8.8 6.7* No data Description Dorsal-fin rays VII-I-I, 10; anal-fin rays III, 7; pectoral-fin 1 st anal-fin spine length 1.6 1.6* No data rays 15; lateral line scales 48; gill rakers 10 (including 6 rudi- 2 nd anal-fin spine length 6.1 5.0* No data ments) + 11 (including 1 rudiments) = 21 in right side, 10 (4 3 rd anal-fin spine length 10.5 9.6 No data rudiments) + 17 (7 rudiments) = 27 in left side; vertebrae 10 + Pelvic-fin spine length 12.8 11 No data 15. Measurements are given in table I. Body elongate, moder- 1st dorsal-fin base 15.1 17.5* No data ately compressed. Mouth large, gape oblique; posterior margin 2 nd dorsal-fin base 14.0 15.8* 15.0 of maxilla reaching to below anterior margin of pupil; lower jaw projecting when mouth closed; symphysis of lower jaw not Anal-fin base 14.0 11 No data protruded. One or two rows of villiform teeth with a few coni- Pectoral-fin length 26.0 24 25 cal teeth on vomer and palatines. Single row of inwardly direct- Pelvic-fin length 17.7 15.0* 14.7 ed conical teeth on upper jaw; villiform teeth band present on Caudal-peduncle depth 10.4 10 9.5 inside of upper jaw. Single row of developed conical teeth on Caudal-peduncle length 24.9 21 No data lower jaw. Two pairs of inwardly directed canine teeth near

Gill-raker length (left/right) 2.0/1.9 3.3/3.5 2.5/2.8 symphyseal region of both jaws. Eye large, oval, its horizontal diameter sub-equal to snout length. Posterior margin of opercle Luminous-gland length 13.2 14.6* No data with two weak spines. Preopercle thin, weakly serration on posterior corner. Posteroventral margin of interopercle with small number of tiny spines forming weak serration. Subopercle thin, ly developed, proximal radial of first pterygiophore lacking trough anteroventral margin weakly serrated, posterior part lacking thin or hollow. Luminous gland short, O-shaped, around anus ( Fig. 1B ). flap. Anus nearer to pelvic-fin base origin than to origin of anal fin. Colour in alcohol ( Fig. 1A ). – Body and head light tan, oper- Scales thin, deciduous; weakly ctenoid on body and bases of sec- cular, branchiostegal rays, and ventral surface of abdomen light ond dorsal and anal fins except for axil of pectoral fin and cheek brown, anus pale bordered by black pigments. (cycloid). Eighth dorsal-fin spine between first dorsal and second dorsal fins isolated, short, thick. Pectoral fin long (right side lack- Distribution ing), slender, posterior tip just reaching to vertical line from origin West coast of New Caledonia ( Fourmanoir, 1988); off Okinawa, of second dorsal fin. Anal fin originating beneath a vertical drawn Japan ( Yamanoue and Toda, 2008); and west of Vanuatu (present through middle of second dorsal-fin base; anal fin spines moderate- study); at 275-360 m depth (Fig. 2). Remarks

Acropoma lecorneti is unique in the genus in having an O-shaped luminous gland surrounding the anus. The luminous-gland length of the present specimen and a Japanese specimen ( NSMT-P 75219 ) were 13.2% SL and 14.6% SL, respectively. We could not make an examination of the luminous gland of the holotype of A. lecorneti , owing to its unknown whereabouts ( R. Causse, pers. comm.). Selected characters of the three specimens of the species are compared in table I .

Yamanoue and Toda (2008) reported that the gill rakers of a Japanese specimen of A. lecorneti are difficult to count, owing to small tooth plates on the gill arch that could not easily be discrimi- nated from gill rakers. Similarly, the present specimen has small tooth plates and many rudimental gill rakers on the gill arch. Fur- thermore, the gill rakers of A. lecorneti being greatly different on both sides (Fourmanoir, 2008; Yamanoue and Toda, 2008; present study), it is not usable as a diagnostic character. Whereas, in all other congeners, most of gill rakers of these species developed and only a few rudiments occurred on the gill arch compared to A. lecorneti . This character is thus useful for distinguishing other species ( Okamoto and Ida, 2002).

The present specimen and a Japanese specimen of A. lecorneti were a male with a fully ripe testis and a female with a great number of eggs (the most developed eggs ca. 0.5 mm in diameter), respectively. Acropoma lecorneti is the largest species in the genus, reported by Fourmanoir (1988) from the holotype measuring 326 mm SL. The other congeneric species mature at ca. 40-100 mm SL, and do not reach 200 mm SL ( Okamoto, 2014).

Acknowledgments. – We sincerely thank P. Pruvost, R. Causse, and Z. Gabsi ( MNHN), G. Shinohara and M. Nakae ( NSMT) for specimen loans, and J. K. Dooley (Adelphi University) for critical reading of the manuscript. Also, the opinions, findings and conclusions or recommendations expressed in this publication generated by the NRF supported research are those of the authors and the NRF accepts no liability whatsoever in this regard. The present material was collected during the SANTO 2006 Expedition organ- ized by Muséum national d’Histoire naturelle, Paris ( MNHN), Pro Natura International ( PNI), and Institut de Recherche pour le Développement ( IRD). The expedition operated under a permit granted to Dr P. Bouchet by the Environment Unit of the Government of Vanuatu. The Marine Biodiver- sity part of the expedition, was specifically funded by grants from the Total Foundation, the Sloan Foundation and the Stavros Niarchos Foundation.We thank Dr Bertrand Richer de Forges and Sarah Samadi, Principal Investiga- tors on board R / V Alis, who collected the specimens.

Figures

Figure 1. – Acropoma lecorneti, MNHN-IC-2008-1612, 141.9 mm SL, from Vanuatu. A: Lateral view of left side; B: Inside of the abdominal region of right side (dissected and outlined luminous gland).