Lophiomus nigriventris sp. nov., 2024

Chen, Hsuan-Pu, Lee, Mao-Ying & Chen, Wei-Jen, 2024, Integrative taxonomy reveals unanticipated hidden diversity in the monotypic goosefish genus Lophiomus (Teleostei, Lophiidae), with description of three new species and resurrection of Chirolophius laticeps Ogilby, 1910, European Journal of Taxonomy 943, pp. 239-287 : 271-274

Lophiomus nigriventris sp. nov.

urn:lsid:zoobank.org:act:9F783F26-5547-4346-8C08-3B1B59B8DB31

Fig. 13 , 15D , 16C ; Tables 3–6

Lophiomus setigerus (not Vahl, 1797) – Caruso 1983: 13 (in part).

Diagnosis

This new species can be separated from other congeners by the combination of dorsal-fin spines 6, pelvic-fin rays 6, pectoral-fin rays 23–24, pale khaki body coloration, peritoneum with dark pigmentation, and reticulate dark pattern on the light floor of the mouth.

Differential diagnosis

Lophiomus nigriventris sp. nov. closely resembles its sibling, Lm. carusoi sp. nov., in terms of pectoral-fin ray counts, peritoneum pigmentation, and the pattern on the floor of the mouth. However, distinctions include the absence of cirri in the pennant-like esca flap (tassel-like or pennant-like flap with moderately long cirri in Lm. carusoi ), a shorter DS4 (8.4–17.3% SL vs 16.7–24.0% SL in Lm. carusoi ), a narrower SNW (31.8–39.5% HL vs 41.9–55.7% HL in Lm. carusoi ), ISP (40.6–45.4% HL vs 48.6–56.7% HL in Lm. carusoi ) and OPSOP (47.3–53.6% HL vs 55.5–65.7% HL in Lm. carusoi ).

Furthermore, this newly described species can be distinguished from the potential sympatric species Lm. setigerus by its pale khaki body coloration (brown in Lm. setigerus ), a dark peritoneum (gray in Lm. setigerus ), and the light floor of the mouth with a reticulate dark pattern (dark floor of the mouth with circular or irregular light patterns in Lm. setigerus ).

Etymology

The name nigriventris is derived from the Latin ‘ niger ’ (meaning ‘black’) plus ‘ venter ’ (meaning ‘belly’). It refers to the black peritoneum of the adult.

Material examined

Holotype

SOUTH CHINA SEA • 193.2 mm SL, sample ID: WJC5808; West Pacific, South China Sea, Macclesfield Bank , stn CP4149; 114°23′ E, 16°07′ N; 162–165 m deep; 26 Jul. 2015; RV Ocean Researcher 1; beam trawl; ZhongSha 2015 exped.; GenBank nos: OR263455 (COI), OR257536 (cytb), OR260588 (rhodopsin); Voucher: NTUM15096 .

Paratypes WETERN PACIFIC • 34.8 mm SL, sample ID: PNG3184; Papua New Guinea, north off Kavieng, stn CP4457; 150°41′ E, 02°33′ S; 133–178 m deep; 2 Sep. 2014; RV ALIS; beam trawl; KAVIENG 2014 exped.; GenBank nos: OR263441 (COI), OR257534 (cytb), OR260577 (rhodopsin), OR257555 (RAG1); Voucher: NTUM12188 .

SOUTH CHINA SEA • 147.4 mm SL, sample ID: WJC5708; Northwestern Pacific, South China Sea, W of Luzon Island, Macclesfield Bank of Zhongsha Atoll , stn CP4146: 114°16′ E, 16°09′ N; 232– 314 m deep; 26 Jul. 2015; RV Ocean Researcher 1; beam trawl; ZhongSha 2015 exped.; GenBank nos: OR263450 (COI), OR257537 (cytb); Voucher: NTUM15094 • 220.8 mm SL, sample ID: WJC5709; same data as for preceding; Voucher: NTUM15094 • 185.0 mm SL, sample ID: WJC5796; same data as for preceding, stn CP4148; 114°19′ E, 16°07′ N; 218–281 m deep; 26 Jul. 2015; Voucher: NTUM15094 • 189.7 mm SL, sample ID: WJC5807; same data as for preceding; GenBank no.: OR263453 (COI); Voucher: NTUM15095 • 192.1 mm SL, sample ID: WJC5809; same data as for preceding, stn CP4149; 114°23′ E, 16°07′ N; 162–165 m deep; 26 Jul. 2015; GenBank no.: OR263454 (COI); Voucher: NTUM15096 .

Description

Adult

MEASUREMENTS AND MERISTIC COUNTS. Morphometric values given in Tables 3 and 4 . Dorsal-fin spines 6; dorsal-fin rays 8; anal-fin rays 6; pectoral-fin rays 23-24; pelvic-fin rays 6; branchiostegal rays 5; quadrate spine 1; interopercular spines 2; vertebrae 18; outermost row of premaxillary teeth 17–24 ( Tables 5–6 ).

HEAD AND BODY. Head relatively short (28.8%–33.3% of SL, mean 30.9 ± 0.02%) and wide (52.8%– 62.0% of HL, mean 57.8 ± 0.03%); eyes suboval; anterior half of premaxilla with three rows of enlarged teeth, largest on innermost row, followed by single row of small teeth on posterior half; maxilla toothless; palatine with single row of small teeth with some enlarged; dentary with three rows of teeth, outer teeth minute and innermost teeth largest; fifth ceratobranchial with two rows of small teeth, forming V-shaped patch; teeth on second and third pharyngobranchials forming small and rounded patches; gill rakers and pseudobranch absent. Palatine spines sharp, with posterior one stronger; frontal ridges and outer surface of maxilla bones bearing low and conical knobs; frontal spines blunt, with posterior one sharper, stronger, and projected posteriorly; inner sphenotic spines low and blunt; outer sphenotic spines blunt, stronger than inner one, sometimes bearing two knobs; pterotic spines broad and blunt; parietal, epiotic, and posttemporal spines short and blunt, inconspicuous; articular spines strong and sharp, with single spine anterior to jaw joint and projected upward; quadrate spines strong and sharp; hyomandibular spines blunt; opercular spines blunt; interopercular spines strong and sharp; subopercular spines blunt, with posterior one inconspicuous; cleithral spines strong and blunt; humeral spines well developed, with three to four sharp spinelets at its tip; edge of head and caudal peduncle covered by pale tendrils.

FINS. Illicium short to moderately long (16.5%–29.0% of SL, mean 23.6 ±0.04%), without tendrils and extending to base of third dorsal spine; esca pennant-like flap without cirri, with one or two dark, small, bulb-like appendages at base of esca; second dorsal-fin spine relatively short (17.9%–20.7% of SL, mean 19.5 ± 0.01), stout, reaching between parietal spines and base of third dorsal-fin spine, with dark tendrils; third dorsal-fin spine relatively short (18.9%–24.0% of SL, mean 21.2 ± 0.02%), slender, reaching from about ½ to ⅔ of retracted fourth dorsal-fin spine, base imbedded under skin, without tendrils; fourth dorsal-fin spine slender, about basal ⅓ imbedded under skin and with dark tendrils, reaching origin of dorsal-fin; fifth and sixth dorsal-fin spines short, mostly imbedded under skin and with dark tendrils; first dorsal-fin ray relatively close to second, both imbedded under skin, last two rays short; anterior three anal-fin rays imbedded under skin.

COLORATION (PRESERVED). Body color khaki with pink penetrates on cheeks and caudal peduncle, covered by minute pale spots densely and blackish-brown spots scarcely on dorsal surface; ventral surface pale, with peritoneum black; floor of mouth light with reticulate dark pattern; dorsal surface of pectoral-fins dark apically and pigmented as adjacent area of body basally; dorsal-fin pale; caudal fin dark basally and apically, with color pattern same as adjacent area of body.

COLORATION ( FRESH). Body color khaki, covered by minute pale spots densely and blackish-brown pigment spots scarcely on dorsal surface; dorsal surface of pectoral-fins blackish brown with color pattern same as adjacent area of body basally; dorsal-fin pink; caudal fin dark basally and pink posterior ⅔, with color pattern same as adjacent area of body.

Subadult

Morphometric values given in Tables 3 and 4 . Description similar to adult, except body color darker and with more blackish-brown pigment spots on dorsal body surface; floor of mouth with reticulate dark pattern, darker and more conspicuous than adults; peritoneum light; caudal fin pale.

Distribution

South China Sea, Macclesfield Bank at depths of 162–314 m (holotype and nine adult paratypes); West Pacific, north off Kavieng at depths of 133–178 m (one subadult paratype); Indian Ocean, waters off Exmouth Gulf at depths of 391 m and 400 m (two sequences from the BOLD systems) (this study, Fig. 1 ).

Remarks

This new species exhibits a potential sympatric distribution with Lm. setigerus ( Fig. 1 ) and could be interpreted as an extreme manifestation of intraspecific variation within the previously defined Lm. setigerus , as observed by Caruso (1983). Caruso’s observations include characteristics such as “pigmentation of peritoneum variable, … dark extremely rare”, and “Coloration in preserve uniform light to dark brown dorsally”, along with a broad range of pectoral-fin rays (21–25; Table 5 ). Notably, the localities of 75% (39 of 52) of the specimens examined by Caruso (1983: 13–14) correspond to the distribution range of Lm. setigerus reported in this study. Additionally, the mean pectoral-fin ray count of Lm. setigerus sensu Caruso (1983) is 22.8, falling within the range of the currently defined Lm. setigerus (21–23, mostly 22). These observations suggest that the taxon described as Lm. setigerus sensu Caruso (1983) was mostly based on true Lm. setigerus , with some rare individuals displaying deviated morphologies that should be attributed to interspecific variation between Lm. setigerus and Lm. nigriventris sp. nov., as described herein.

Figures

Fig. 13. Lophiomus nigriventris sp. nov. A–D. Holotype (NTUM15096, sample ID: WJC5808). E–H. Subadult paratype (NTUM12188, sample ID: PNG3184). A. Preserved specimen, dorsal view. B. Ditto, ventral view. C. Ditto, fresh specimen. D. Ditto, floor of mouth. E. Preserved specimen, dorsal view. F. Ditto, ventral view. G. Ditto, fresh specimen. H. Ditto, floor of mouth.

Fig. 15. X-ray radiographs in dorsal view and zoom-in images of left pectoral-fin of Lophiomus spp. collected in this study for visualizing interspecific variations in pectoral-fin ray counts. A. Lm. setigerus (Vahl, 1797), neotype (NTUM10408, sample ID: WJC0905). B. Lm. laticeps (Ogilby, 1910) stat. rev. (NTUM13463, sample ID: NC1375). C. Lm. immaculioralis sp. nov., holotype (NTUM16313, sample ID: WJC7777). D. Lm. nigriventris sp. nov., holotype (NTUM15096, sample ID: WJC5808). E. Lm. carusoi sp. nov., holotype (MNHN 2024-0099, sample ID: NC2059).

Fig. 16. Esca of Lophiomus spp. A. Lm. laticeps (Ogilby, 1910) stat. rev. (NTUM13463, sample ID: NC1375). B. Ditto (NTUM13468, sample ID: NC964). C. Lm. nigriventris sp. nov., holotype (NTUM15096, sample ID: WJC5808). D. Lm. immaculioralis sp. nov., holotype (NTUM16313, sample ID: WJC7777). E. Lm. carusoi sp. nov., holotype (MNHN 2024-0099, sample ID: NC2059). F. Ditto, paratype (NTUM17682, sample ID: NC1978).G. Lm. setigerus (Vahl, 1797) (NTUM14414, sample ID: WJC7223). H. Ditto (NTUM14414, sample ID: WJC7224). Scale bars = 1 mm.

Fig. 1. Bathymetric terrain map of eastern Indian Ocean and West Pacific showing the occurrence points of species of Lophiomus Gill, 1883 based on the samples/sequences included in the analyses of this study. White circle: type locality of the species of Lophiomus.