Gigantactis cheni, Ho & Shao, 2019

Ho, Hsuan-Ching & Shao, Kwang-Tsao, 2019, Two new deep-sea anglerfishes (Oneirodidae and Gigantactidae) from Taiwan with synopsis of Taiwanese ceratioids, Zootaxa 4702 (1), pp. 10-18 : 10-18

publication ID

https://doi.org/ 10.11646/zootaxa.4702.1.5

publication LSID

lsid:zoobank.org:pub:F7BCE3B0-220C-466F-A3A5-1D9D2606A7CA

DOI

https://doi.org/10.5281/zenodo.5618092

persistent identifier

https://treatment.plazi.org/id/48DD1126-5D2F-468B-8C2A-00DBC0FCBE2D

taxon LSID

lsid:zoobank.org:act:48DD1126-5D2F-468B-8C2A-00DBC0FCBE2D

treatment provided by

Plazi

scientific name

Gigantactis cheni
status

sp. nov.

Gigantactis cheni sp. nov.

Hairy whipnose

Figs. 3 View FIGURE 3 A–C

Holotype. ASIZP 62947 View Materials , female, 385 mm SL, off Daxi , Yilan, northeast Taiwan, ca. 24°50 N, 122°00 E, ca. 400– 500 m, bottom trawl, Oct. 2001, bycatch, coll. D.-M. Chen. GoogleMaps

Paratype. ASIZP 61823 View Materials , female, 340 mm SL, May 2002 ; NMMB-P006230 , female, 325 mm SL, Nov. 8, 2007 ; both collected from near the type locality by D.-M. Chen.

Diagnosis. A member of the Gigantactis vanhoeffeni species group differing from congeners in having a single row of 8–15 unpigmented filaments present on posterior margin of basal one-third of illicium; illicial length 145.5– 172.1% SL; esca elongated, tapering into a conical shape, with numerous spinules, and darkly pigmented; distal prolongation length 10.6–12.6% SL; dentary teeth 66–70 on each side, arranged in 5 longitudinal series; dentary teeth relative long, 2.5–3.4% SL; caudal fin rays short, 25.5–30.6% SL; and caudal fin deeply forked.

Description. Dorsal-fin rays 6, anal-fin rays 6, pectoral-fin rays 17, caudal-fin rays 9. Dentary teeth 66–70 on each side, 136 (136–140) in total; premaxillary teeth 26–32 on each side; lower jaw with five series of teeth, two inner rows, one middle row, and 2 outer rows ( Fig. 3C View FIGURE 3 ). Head length 19.7–21.5% SL; head depth 10.6–12.4% SL.

Body laterally compressed; caudal peduncle elongate; head short; dermal spinules present on entire body surface except lips; illicium emerging from stout tip, 15 (8–12 in paratypes) unpigmented filaments along posterior margin of basal one-third of illicial stem, 10 (5–8) on dorsal surface of head just behind the base of illicium; illicium relative long, 145.5–172.1% SL. Papilliform gland present inside of upper oral cavity.

Escal bulb tapering, with a long black-pigmented prolongation, 10.6–12.6% SL; surface spinulose except the escal pore; short filaments present on prolongation and the terminal tip.

Distribution. Gigantactis cheni is represented by the type series collected from northeastern Taiwan off Daxi at depth ca. 400– 500 m.

Etymology. Gigantactis cheni is named for Mr. Din-Moo Chen, an excellent fisherman who collected most samples for our studies, including the type series of both new species in present work.

Remarks. Gigantactis cheni sp. nov. belongs to the G. vanhoeffeni species group (Bertelson et al., 1981) and differs from all other members of this group in having a considerably longer illicium and a longer distal prolongation of the escal bulb. It is most similar to G. paxtoni Bertelsen, Pietsch & Lavenberg, 1981 which also has unpigmented filaments on illicium. However, the new species differs in having relatively more total jaws teeth (136–140, vs. 10–55), relatively short outtermost teeth (2.5–3.4%, vs. 3.4–7.1% SL); slightly shorter illicium (145.5–172.1%, vs. 168.0–198.0% SL); a relatively short escal prolongation (10.6–12.4%, vs. 12.0–28.0% SL); a relatively short caudal fin (25.5–30.6%, vs. 27.5–35.0% SL); and caudal fin deeply forked (vs. nearly truncate). Also, the filaments on the head are distributed on the posterior illicium for about one-third its length, whereas those on G. paxtoni are restricted to the basal region of illicium.

Gigantactis cheni sp. nov. is also similar to G. meadi Bertelsen, Pietsch & Lavenberg, 1981 , but differs in having a relatively long illicium (145.5–172.1%, vs. 72–96% SL), a relatively elongated esca (vs. short), caudal fin deeply forked ( Fig. 3A View FIGURE 3 , vs. slightly concaved).

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