Lophiomus immaculioralis 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 : 269-271

Lophiomus immaculioralis sp. nov.

urn:lsid:zoobank.org:act:F6FE6067-613F-41C5-8C0E-7750F473F7EE

Figs 12 , 15C , 16D ; Tables 3–6

Diagnosis

This new species can be separated from other congeners by the combination of dorsal-fin spines 5, pelvic-fin rays 7, pectoral-fin rays 21–22, OPSOP 22.2% of HL, brown body coloration, and the absence of conspicuous dark marking on the light floor of the mouth.

Differential diagnosis

Lm. immaculioralis sp. nov. is most similar to its sister species Lm. setigerus in brown body coloration and pectoral-fin ray counts but differs in having a lower count of dorsal-fin spines (5 vs 6 in Lm. setigerus ), shorter OPSOP (22.2% HL vs 46.1–60.0% HL in Lm. setigerus ), a tassel-like flap esca (mostly pennant-like in Lm. setigerus ), and a peritoneum without dark or gray pigmentation (gray in Lm. setigerus ).

Since this new species is described based on a single specimen, the molecular differential diagnosis between the two species at COI gene level shown below is especially provided for aiding species identification: Nos. 45 (T vs C), 87 (G vs A), 90 (G vs A), 102 (T vs C), 103 (T vs C), 105 (A vs G), 106 (G vs C), 168 (T vs C), 177 (A vs G), 204 (C vs T), 207 (G vs A), 210 (C vs T), 255 (A vs G), 273 (C vs T), 282 (C vs T), 337 (C vs T), 348 (A vs G), 363 (G vs A), 369 (T vs C), 372 (G vs A), 453 (C vs T), 522 (A vs G), 555 (G vs A), 558 (G vs A), 561 (C vs T), 585 (T vs A), 618 (T vs C). Numbering of the position starts from the first nucleotide site of the gene. The differences can translate into a 4.9% sequence divergence.

Etymology

The name immaculioralis is derived from the Latin ‘ immaculi- ’ (meaning ‘unstained’) plus ‘ oralis ’ (meaning ‘oral’). It refers to the floor of the mouth in this species being light, without conspicuous dark pigmentation.

Material examined

Holotype

ANDAMAN SEA • 243.0 mm SL, sample ID: WJC7777; Thailand, Ranong, Ranong fish landing port; ca 100–200 m deep; 21 Mar. 2018; GenBank nos: OR261060 (COI), OR257552 (cytb), OR260579 (rhodopsin), OR257564 (RAG1); Voucher: NTUM16313 .

Description

Adult

MEASUREMENTS AND MERISTIC COUNTS. Morphometric values given in Tables 3 and 4 . Dorsal-fin spines 5; dorsal-fin rays 8; anal-fin rays 6; pectoral-fin rays 21–22; pelvic-fin rays 7; branchiostegal rays 5; quadrate spine 1; interopercular spines 2; vertebrae 19; outermost row of premaxillary teeth 33–35 ( Tables 5–6 ).

HEAD AND BODY. Head relatively short (31.9% of SL) and narrow (54.9% of HL); 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, dentary, and quadrate bones bearing low and conical knobs; frontal spines sharp, with posterior one sharper, stronger, and bearing small knobs; inner sphenotic spines blunt, low, and broad; outer sphenotic spines sharp and strong; pterotic, parietal, epiotic, and posttemporal spines low, broad, and blunt; articular spines sharp and strong, with single spine anterior to jaw joint; quadrate spines sharp and strong; hyomandibular spines low but sharp; opercular spines blunt, low, and broad; interopercular and subopercular spines strong and sharp; cleithral spines strong; humeral spines well developed, with five sharp spinelets at tips; edge of head and caudal peduncle covered by black tendrils.

FINS. Illicium short (30.7% of SL), without tendrils and reaching basal ⅓ of retracted third dorsal-fin spine; esca tassel-like flap with long dark cirri; second dorsal-fin spine relatively short (18.3% of SL), slender, reaching position of inner sphenotic spines, with dark tendrils; third dorsal-fin spine relatively short (23.5% of SL), pale and slender, reaching from about ⅓ of retracted fourth dorsal-fin spine, without tendrils; fourth dorsal-fin spine pale, slender, without tendrils; fifth dorsal-fin spine long, mostly imbedded under skin; sixth dorsal-fin spine absent; posterior dorsal-fin rays shorter than anterior.

COLORATION (PRESERVED). Body color reddish brown, uniformly covered with irregularly shaped pale spots on dorsal surface, denser in caudal peduncle; ventral surface pale, with peritoneum light; floor of mouth light, without conspicuous dark marking, with minute dark spot scarcely; dorsal surfaces of pectoral-fins dark apically and pigmented as adjacent area of body basally; dorsal-fin and dorsal-fin rays pale; caudal fin dark basally and apically, with color pattern same as adjacent area of body.

COLORATION ( FRESH). Same as preserved coloration.

Subadult

Unknown.

Distribution

Andaman Sea, waters off Ranong, Thailand (holotype) (this study, Fig.1 ).

Remarks

Comparing with two previously described nominal species of Lophiomus that are also distributed in the Indian Ocean, namely Lp. indicus and C. malabaricus , this new species is different from both by having floor of mouth without conspicuous dark marking (black with circular white patches in Lp. indicus , unknown in C. malabaricus ), lower pectoral-fin ray count (21–22 vs 22–23 in Lp. indicus , 24 in C. malabaricus ), and lower dorsal-fin spine count (5 vs 6 in both nominal species) ( Figs 9C, G , 12D ; Tables 1 , 5 ). Given the non-overlapping distribution between two nominal species (Andaman Sea off Ranong vs Bay of Bengal, for Lp. indicus and Kerala coast, southwest India, for C. malabaricus ) ( Fig. 1 ; Table 1 ), along with substantial genetic differences (16.1% at COI gene) to ‘ Lp. indicus ’ ( Table 7 ; Fig. 2 ) and the mentioned morphological distinctions, this new species is considered a distinct species from the two nominal species from the Indian Ocean.

Figures

Fig. 12. Lophiomus immaculioralis sp. nov., holotype (NTUM16313, sample ID: WJC7777). A. Preserved specimen, dorsal view. B. Ditto, ventral view. C. Ditto, fresh specimen. D. 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.

Fig. 9. Lophius indicus Alock, 1889. A–D. Large syntype (BMNH 1890.11.28.45). E–H. Small syntype (BMNH 1890.11.28.45.46). A. Preserved specimen, dorsal view. B. Ditto, ventral view. C. Ditto, floor of mouth. D. Ditto, X-ray radiograph. E. Preserved specimen, dorsal view. F. Ditto, ventral view. G. Ditto, floor of mouth. H. Ditto, X-ray radiograph. Photographed by L. Goodayle. © Trustees of the Natural History Museum, London (available under CC-BY 4.0).

Fig. 2. Maximum-likelihood phylogenetic tree of the species of Lophiomus Gill, 1883 based on the MT dataset (1806 bp, COI: 663 bp; cytb: 1143 bp; TN+ F +I (1–663 bp), GTR+ F +I+G4 (664–1806 bp)) with species delimitation analyses (vertical bars on the right side of the tree). Branch lengths of the phylogenetic tree are proportional to the inferred nucleotide substitutions except for the one connecting to the distant outgroup of Lophiodes mutilus. Node numbers represent ‘SH-aLRT/ UFBoot’ values in percent (%). Locality abbreviations: AU = Australia (NSW = New South Wales; Qld = Queensland; WA = Western Australia); CS = Coral Sea; HN = Hainan Island; IN = India; NC = New Caledonia; PH = Penghu Island; PL = Philippine; PNG = Papua New Guinea; SCS = South China Sea; TH = Thailand; TW = Taiwan. Text next to final decisions represents inferred taxon names and numbers of supported criteria covering all available criteria, with proportions in parentheses.