Bellottia robusta
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BibTeX: @article{Nielsen2009Zootaxa2018, RIS/ Endnote: TY - JOUR Wikipedia/ Citizendium: <ref name="Nielsen2009Zootaxa2018">{{Citation |
Ordo: Ophidiiformes
Familia: Bythitidae
Genus: Bellottia
Name
Bellottia robusta Nielsen, Jørgen G., 2009 – Wikispecies link – Pensoft Profile
- Bellottia robusta Nielsen, Jørgen G., 2009, Zootaxa 2018: 47-51.
Materials Examined
Material examined (12 specimens, SL 43–82): Holotype: USNM394117, SL 62, male, Gulf of Mexico, Green Canyon 234, 27° 45 ’N, 91 ° 13 ’W, st. JSL- 4712, 535 m, coll. C. Fisher, 10 July 2004. Paratypes: TCWC10956.01, SL 64, female, Gulf of Mexico, 27 ° 46.96 ’N, 91 ° 30.46 ’W, st: BH AT 1, 98 GOM JSL 4035, 540 – 580 m, coll. Tracy Ward, 7 Aug. 1998. - TCWC10957.01, SL 53, female, Gulf of Mexico, 27 ° 44.7 ’N, 91 ° 13.3 ’W, st: GC AT 1, 98 GOM JSL 4033, 540 m, coll. Tracy Ward, 7 Aug. 1998. – USNM394118, SL 34, male,Gulf of Mexico, Green Canyon 232, 27° 44.49 ’N, 91 ° 19.07 ’W, st. JSL- 4437, 569 m, coll. C. Fisher, 24 June 2002. – USNM394119, SL 35, male, Gulf of Mexico, Green Canyon 234, 27° 44.78 ’N, 91 ° 13.30 ’W, st. JSL- 4569, 538 m, coll. C. Fisher, 26 Aug. 2003. – USNM394120, SL 49, male, Gulf of Mexico, Garden Banks 543, 27° 27.32 ’N, 93 ° 11.29 ’W, st. JSL- 4582, 546 m, coll. S. Hourdez, 3 Sep. 2003. – USNM394121, SL 82, female, and ZMUC P 771652, female, Gulf of Mexico, same data as for holotype. – USNM394122, SL 77, female, and ZMUC P 771653, SL 72, male, Gulf of Mexico, Green Canyon 234, 27° 45.80 'N, 91 ° 13.30 ’W, st. JSL- 4713, 532 m, coll. C. Fisher, 10 July 2004. – USNM394123, SL 50, male, Gulf of Mexico, Green Canyon 234, 27° 44.76 ’N, 91 ° 13.46 ’W, st. JSL- 4720, 506 m, coll. K. Zelnio, 13 July 2004. – USNM394124, SL 51, male, Gulf of Mexico, Green Canyon 234, 27° 44.76 ’N, 91 ° 13.46 ’W, st. JSL- 4721, 506 m, coll. C. Fisher, 14 July 2004.
Condition of material. In most specimens the body is much curled up and the mouth wide open making precise measurements difficult to obtain.
Diagnosis
Diagnosis.Bellottia robusta differs from its congeners by the following combination of characters: depth at origin of anal fin 17.5 –23.0 % SL, small teeth blunt or pointed, four spines on hind margin and one on crest of preopercle, distinct spine on cleithrum above base of pectoral fin, anterior gill arch with 5–6 long rakers, predorsal 44.0– 49.5 % SL and precaudal vertebrae 12. Similarity.Bellottia robusta is most similar to B. cryptica, in e. g. presence of a spine on cleithrum and in fin ray and total vertebral counts, but differs by the heavier body (17.5 –23.0 vs 17.0 % SL at origin of anal fin), origin of anal fin below dorsal fin ray 10–15vs8, precaudal vertebrae 12vs10 and spine on preopercular crest vs no spine in B. cryptica. It differs from B. apoda by the deeper (17.0–23.0 vs 13.0–16.0 % SL) and darker body, more caudal fin rays (7vs6), poorly developed fangs (vs distinct, retrorse fangs), more long rakers on anterior gill arch (5–6vs3–4) and longer predorsal (44.0– 49.5vs35.5 –40.0 % SL). From B. galatheae it differs e. g. by the higher number of rays in dorsal (85 – 83vs70–72), caudal (7vs6), anal (75–88vs61) and pectoral (23–25vs19–20) fins. From B. armiger it differs by having more precaudal vertebrae (12vs10), more caudal fin rays (7vs6) and a larger predorsal length (44.0– 49.5vs41.5 % SL).
Description
Description. The principal meristic and morphometric characters are shown in Table 1. The description is based mainly on the holotype. Differences of paratypes are given in brackets and in Table 1.
B. robusta B. cryptica B. apoda Gulf of Mexico West. Atl. East. Atl. + Med. HT HT+ 11paratypes Holotype n= 16 including LT Body robust, highest near base of pectoral fin, completely covered with oval, ca. 1.5 mm, cycloid scales. Anterior segment of lateral line extending close to dorsal margin of body and from above anus along midline of body. Head profile convex, cheek and gill-cover scaled, while rest of head naked. Mouth slightly oblique with posterior margin of maxillary vertically expanded ending well behind eye. Anterior nostril closer to upper lip than to posterior nostril, both with low rim. Small opercular spine strong and pointed, almost completely covered by skin, and not reaching posterior margin of opercle (a few specimens with spine reaching just beyond hind margin of opercle). Ventral margin of preopercle with four distinct spines and one spine on preopercular crest (Fig. 3) (spine often covered by skin; one specimen with two spines on crest). Origin of dorsal fin above tip of pectoral fin, anal fin origin just behind midpoint of fish (some specimens with preanal up to 59 % SL). Pectoral fin placed on mid-body level with peduncle higher than long. A distinct spine on cleithrum just above base of pectoral fin (one specimen with spine ending in a blunt tip). Anterior gill arch with 2–3 (2–4) plate-like rakers on upper branch, one long raker in the angle between the two branches and lower branch with 4–5 long rakers, followed by seven (6–9) plate-like rakers. Longest gill filament slightly shorter than longest raker. Two minute pseudobranchial filaments. Standard length62 34–82n42 26–65n Meristic characters Dorsal fin rays87 85(88.8)93 10 92 83(89.0)94 14Caudal fin rays7 7 10 7 6 14Anal fin rays81 75(81.2)88 12 84 68(74.0)82 15Pectoral fin rays24 23(23.9)25 11 23 21(22.9)26 12Precaudal vertebrae12 12 11 10 12(12.6)13 15Caudal vertebrae38 36(37.6)39 11 39 33(36.0)37 15Total vertebrae50 48(49.3)51 11 49 46(48.5)50 15Pseudobranchial filaments2 2 12 2 0(1.2)2 15Anterior dorsal ray above vertebra no.10 10(10.4)11 10 11 8(8.9)10 15Anterior anal ray below dorsal ray no.10 10(12.6)15 10 8 17(18.2)19 13Anterior anal ray below vertebra no.14 14(15.3)16 11 14 15(15.7)17 15Long gill rakers5–6 5(5.3)6 12 5–6 3(4.0)4 16Total gill rakers15 14(15.7)18 11 17 11(13.5)16 15Spines on preopercle m margin4 4 12 4 3(4.1)5 16Spines on preopercle crest1 1–2 12 0 1 16Morphometric characters in % of SL Head length31.0 27.5(30.0)32.0 11 32.0 26.5(28.4)30.5 15Depth at anal fin origin22.0 17.5(20.0)23.0 11 17.0 13.0(14.5)16.0 12Upper jaw length15.0 14.0(15.0)16.0 11 14.5 13.5(15.0)16.0 15Depth of posterior maxillare5.3 4.3(4.9)5.6 11 5.1 4.2(4.8)5.3 13Dia. eye window5.3 4.7(5.2)5.5 11 5.5 3.5(4.6)5.8 15Postorbital length19.5 16.5(18.2)20.0 11 18.5 15.5(16.8)18.0 13Preanal length52 52(55.9)59 11 51 51(53.0)56 14Predorsal length49.5 44.0(46.2)49.5 10 46.5 35.5(37.8)40.0 12Length of long gill raker2.3 1.9(2.3)2.6 10 2.2 1.1(1.7)2.3 11
Head pores: Because of thin, often torn skin, pores are difficult to observe. A few, large pores, with three (2–3) in a vertical row behind eye, three below eye and four pores on mandible. Small whitish papillae spread over head. Dentition: Most teeth are small and blunt. Head of vomer slightly curved with one tooth row of ca. ten small, blunt teeth. Posterior half of palatines edentate, and anterior half with one row of small, blunt teeth. Dentaries with posterior fifth edentate and dentigerous part with one tooth row increasing to 2–3 rows at symphysis; outer row with retrorse fangs. Premaxillaries with posterior third edentate and dentigerous part with one tooth row increasing to 4–5 rows at symphysis; outer row with larger, pointed teeth (three specimens with larger, pointed teeth on all dentigerous bones). Axial skeleton (based on radiographs): Tips of neural and haemal spines thin and pointed. Anterior neural spine one third the length of second spine. Neural spines 3–7 (2–7) slightly depressed. Bases of neural spines 4–7 (4–8) enlarged. Parapophyses present on vertebrae 8–12 (7–12) and pleural ribs on 4–10 (3–11). Epipleural ribs indistinct. Otolith (Fig. 2): The 3.5 mm elongate sagittal otolith (from a 64 mm SL paratype, TCWC10956.01) is twice as long as high and twice as high as thick. Dorsal and ventral rim roundish, vaguely pointed posteriorly. Sulcus undivided, 1 / 3 – 1 / 4 the length of the otolith. No osteal channel. Coloration:Fig. 1 shows the holotype after four years of preservation. The body is brownish with light vertical fins. The abdomen, operculum and eye-surroundings dark blue and the rest of the head colored like the body. The body of some of the smaller paratypes is dark brown.
Biology and Ecology
Biology. This species appears to be very closely associated with complex habitat, provided by tubeworms or deep-sea corals (e.g., Lophelia pertusa). Rocky substrata are also likely habitats for B. robusta, even though it has not yet been collected there. This species is well concealed within crevices provided by these habitats, and specimens were not observed prior to collection. Because of its cryptic nature there are no more data on the biology or ecology of this species. A 53 mm specimen (TCWC10957.01) contained eggs up to 0.7 mm in diameter; embryos were not observed.
Etymology
Etymology. The specific name, robusta, refers to the short, deep body.
Distribution
Distribution (Fig. 4). Known from nine localities in a restricted area of the northern Gulf of Mexico all caught by JSL at depths of 506– 580 m.
Taxon Treatment
- Nielsen, Jørgen G.; Ross, Steve W.; Cohen, Daniel M.; 2009: Atlantic occurrence of the genus Bellottia (Teleostei, Bythitidae) with two new species from the Western North Atlantic, Zootaxa 2018: 47-51. doi
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