著者

浅野 博利

出版者

社団法人日本動物学会

雑誌

動物学雑誌 (ISSN:00445118)

巻号頁・発行日

vol.67, no.7, pp.197-201, 1958-07-15

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The present paper deals with the description of a new subspecies Rhynchocymba nystromi ginanago and a new species Promyllantor nezumi, both of which were taken from rather deep waters off southeastern coasts of Japan by deep-sea trawlers. 1. Rhynchocymba nystromi ginanago subsp. nov. Holotype: No. 21440, 241.3mm. in total length, off Owashi, Mie Prefecture, January 25, 1954. Paratypes: Nos. 2045-2047, 2110, 7701, 19019, 19030, 19843, 14989-14991, 15078-15030, 15082-15084, 21439, 21443, 23903-23907 and 24675; 229.5-287.2mm. in total lenth, taken from Owashi and Daiozaki, Mie Prefecture and off Choshi, Chiba Prefecture. Pectoral rays 12-14 (12). Pores in lateral line 35-40 (38) before the vent. Vertebrae 43-46+81-88=126-134. Head 5.90-6.60 (6.49) in total length and 1.35-1.75 (1.56) in trunk length. Head and trunk 2.40-2.62 (2.53) in total length. Snout 3.33-3.89 (3.54) in head length; eye diameter 3.65-4.59 (4.23); interorbital space 5.10-8.25 (5.40); distance from tip of snout to origin of dorsal fin 0.87-0.98 (0.93); pectoral fin length 2.71-3.64 (3.08). Upper lip without well defined free flange, but forms a longitudinal groove along the upper margin. Labial canal with 2 or 3 bony projections from lower edge of preorbital bone. Teeth small, blunted conical in shape, setting in several rows on jaws and vomer. Anterior half of premaxillary patch of teeth expose in front of lower jaw, when mouth is closed. Cleft of mouth reaches a vertical through middle of eye. Tail moderately tapering and not so stout, the tip rounded. Sensory pores 24 on each side of head inclusive of 1 pore on top of occipital region. Pores in lateral line 122-130 (124). Dorsal inserted slightly behind a vertical through base of pectoral. Caudal fin moderately well developed. In formalin head and body light brown above, paler lower. Vertical fins furnished with blackish margin. Remarks: The present subspecies resembles Rhynchocymba nystromi nystromi, but is distinguished from it in having larger number of both lateral line pores and vertebrae, longer trunk, larger eye, blunter snout, and pale oesophagus and stomachal blind sac. The present from also closely related to Wade's species, R. catalinensis, but apparently differs from it in having more numerous pores in lateral line, shorter head, smaller eye and shorter tail. 2. Promyllantor nezumi sp. nov. Holotype: No. 19099, 365.5mm. in total length, off Owashi, Mie Prefecture, November 12-17, 1952. Paratypes: Nos. 1943-1944, 2074, 2109, 2169, 4071, 7904, 13952, 13955-13956, 14993, 14996, 17351-17353, 17383, 17697-17700, 19049-19059, 19100-19106, 20826-20830, 20940-20943, 21377, 21444-21445, 21714, 23888-23902, 24697-24718, 24720-24728, 24730-24754; 181.0-399.3mm. in total length, taken from Mimase market, Kochi Prefecture, off Owashi, Mie Prefecture and off Miya, Aichi Prefecture. Pectoral rays 11-13 (13). Pores in lateral line 36-40 (38) before the vent. Vertebrae 50-54+107-116=160-170. Head 8.20-9.35 (8.92) in total length and 1.67-2.28 (1.82) in trunk length. Head and trunk 2.81-3.24 (3.16) in total length. Snout 3.42-4.33 (4.10) in head length; eye diameter 8.12-11.67 (9.54); interorbital space 6.44-9.38 (6.84); distance from tip of snout to origin of dorsal fin 0.74-0.89 (0.77); pectoral fin length 3.20-5.01 (3.73). Body slender and tapering into pointed tail. Posterior nostril very large, ovoid in shape, opening immediately before antero-inner margin of eye. Upper lip without free flange or groove. Lower edge of preorbital bone sending 2 or 3 bony projections outward and upward. Teeth villiform, in broad band on jaws and vomer the vomerine band especially well developed and becomes progressively wider posteriorly. Premaxillary band of villiform teeth slightly exposed in front of lower jaw on lower surface of well projecting snout, when mouth is closed. Mouth rather small, the gape reaches a vertical through anterior end of pupil. Sensory pores on head not well developed, about 16 on each side. Lateral l