Eviota rubrostriata, Shen & Hung & Chen, 2024

Shen, Kang-Ning, Hung, Tsang-Hsieh & Chen, I-Shiung, 2024, A new species and two newly recorded species of Eviota (Teleostei: Gobiidae) from Taiwan, Zootaxa 5550 (1), pp. 32-40 : 33-35

Eviota rubrostriata n. sp.

( Fig. 1 )

(ĽüDzñṱ)

Materials examined

Holotype —NTOUP-2021-09-302, 18.3 mm SL, Coll. I-S. Chen et al., Sept. 30, 2021, Jifei, Chengkong Town, Taitung County, Taiwan, ROC.

Paratype —NTOUP-2023-08-111, 2 specimens, 13.9–14.7 mm SL, Coll. I-S. Chen, Aug. 18, 2023, Nan-fang-ao, Su-ao, Ilan County, Taiwan, ROC.

Diagnosis

The species can be well distinguished from other congeners by the following combination of features: (1) second dorsal fin I/8, anal fin I/7, pectoral fin 14; (2) longitudinal scale rows 23–24; (3) typical head canal pattern type 2; (4) fifth pelvic fin rays about 8–10% of fourth pelvic fin rays; (5) mouth large, extending to middle vertical of eye; and (6) specific coloration: ventral profile after anus with 6–7 main blackish brown spots; infraorbital band as a wide, deep red through posterior upper lip to lower lip; opercle with a horizontal blackish brown triangular stripe; eye with 5 main brown red regions; first dorsal fin with red spots in distal filamentous anterior 2 spinous rays in male; pectoral fin base with an orange band between two snow white bars; caudal fin base with a vertical black line, in front of line with a pentagon shape of large black spot; and bright yellow above and below black spot.

Description

Body very slender and rather compressed. Eye large and snout rather blunt and short. Gill-opening restricted, extending just to anterior edge of opercle. Interorbital region very narrow. Mouth large, maxillary extending to middle vertical of eye. Vertebral count 26.

Body morphometric proportions from two type specimens as follows: head length 27.1–27.4%; snout to origin of first dorsal fin 36.2–37.5%; snout to origin of second dorsal fin 53.8–56.5%; snout to origin of anal fin 58.7– 61.3%; body depth at anal fin origin 18.1–18.7%; caudal peduncle length 24.3–25.6%; and caudal peduncle depth 12.2–13.9%, which all above in standard length. Eye diameter 29.9–30.8%; postorbital length 54.4–58.1%; snout length 20.3–21.2%; and upper jaw length 38.0–40.2%, which all above in head length.

Fins. —D1 VI, D2 I/8; P 14; A I/7; VI /5+I/5. First dorsal fin with anterior two rays rather elongated to 2/3 basal region of second dorsal fin base in male. Rear of second dorsal fin tip not extending toward vertical of caudal fin base in current male. Fifth pelvic fin ray very short about 8–10% of fourth rays.

No frenum, no connecting membrane between 2 pelvic fins.

Scales.—LR 23-24, TR 8, PreD 0. Body with rather large ctenoid scales. Predorsal region entirely naked. Head, opercle and nape naked.

Head lateral-line system. Same to typical head canal pattern type 2 (see Lachner & Karnella, 1980).

Coloration in fresh material

Body and head translucent with creamy yellow background. Each scale pocket with anterior reddish to brownish curve. Ventral profile after anus with 6–7 main blackish brown spots. Snout with pointed blackish brown mark. Anterior nostril brown. Eye with 5 main brown red regions. Infraorbital band as a wide, deep red stripe through posterior upper lip to lower lip. Nape with a longitudinal orange red stripe. Opercle with a horizontal blackish brown triangular stripe. No any postocular black spot. Mouth pinkish. Chin cheery red to red brown anteriorly.

First dorsal fin with red spots in distal filamentous spinous rays in male; but no elongate extension and red spinous rays in female. Basal region of first dorsal fin grayish. Second dorsal fin with four major basal spots; and its fin with 3 horizontal rows of brown spots. Pectoral fin base with an orange band between two snow white bars. Anal fin grayish with two to three basal orange or red spots. Caudal fin base with a vertical black line, in front of line with a pentagon shape of large black spot. Bright yellow above and below black spot. Caudal fin with 4–5 vertical rows or somewhat oblique rows of brown to black lines. Pelvic fin translucent and whitish.

Etymology

The specific name, rubrostriata , refers to the specific feature of an oblique, deep red stripe (Latin red- rubur; stripestriate). This infraorbital red bar extends from the lower margin of the eye extending to the posterior region of both lips.

Distribution

The new species has been collected and found in Ilan, Hualien, and Taitung Counties of Taiwan. It is also been observed in New Taipei City in northern Taiwan.

Remarks

The new goby, Eviota rubrostriata n. sp., is closely related to the five nominal species within the E. zebrina complex ( Tornabene et al., 2021). Among these species ( Table 1 ), the mouth size (maxillary) is similar to Eviota oculineata , extending to middle vertical of eye (pattern 2 in Table 1 ), unlike the other two groups, E. longirostris and E. zebrina , where the mouth extends only to or in front of anterior margin of pupil (pattern 1), and also unlike E. pseudozebrina and E. marerubrum , where the mouth is much larger and extends far beyond the middle vertical of the eye (pattern 3).

However, the new goby, E. rubrostriata n. sp., can be well distinguished from E. oculineata by the following specific coloration patterns: (1) infraorbital wide bar present vs. entirely no any infraorbital bar; (2) pentagon shape of black spot on caudal fin base in front of posterior black mark vs. oval black spot; and (3) posterior mark as rather long, slender black line with sharp both tips on caudal fin base vs. very similar size of oval spots to anterior part. The type locality is also far away for either species.

The Bayesian tree, derived from 457bp mtDNA COI sequence data, suggests that the new species E. rubrostriata n. sp. (PQ416648 and PQ465619) is within the E. zebrina complex and is mitogenetically closer to the discrete species, E. pseudozebrina from Fiji, with a posterior probability around 0.7 ( Fig. 2 ). The Bayesian tree topology is similar with previous research on the E. zebrina complex ( Tornabene et al. 2021), except for the relative position of E. zebrina with E. marerubrum and E. oculolineata and indicates that the new species is in the same clade as E. gunawanae , E. tetha , and E. pseudozebrina .

Figures

FIGURE 1. Eviota rubrostriata n. sp., A. male, holotype, 18.3 mm SL, male, Jifei, Chengkong, Taitung County, Taiwan; B. female, paratype, 13.9 mm SL, Su-Ao, Ilan County, Taiwan.

FIGURE 2. Bayesian tree of the new species E. rubrostriata n. sp. and its congeneric species in the E. zebrina complex with E. imitata and Trimma okinawae used as the outgroup. The number above the nodes are Bayesian posterior probabilities. Labels include the species name and its GenBank number in NCBI.