Luciogobius newtaipeiensis, Chen & Ren & Jiang & Wang & Chang, 2024

Luciogobius newtaipeiensis sp. nov.

(Ĕ北ṣȇ)

Figures 7–9 View FIGURE 7 View FIGURE 8 View FIGURE 9

Material examined

Holotype. NTOUP-2023-05-305 , 50.2 mm SL, coll. I-S. Chen et al., coast area near Longdong Bay , New Taipei City, Taiwan.

Paratypes. NTOUP-2023-05-306 , 44.3 mm SL, collection date and locality data same as above .

Diagnosis

Luciogobius newtaipeiensis sp. nov. can be distinguished from all other congeneric species by the following unique combination of features: (1) second dorsal fin rays: I/11 and anal fin rays I/12; (2) pectoral fin rays modally 18 and with 1 upper free soft ray; (3) vertebral count: 16 + 20 = 36; (4) a dermal projection on posterior part of eye; and (5) specific coloration: head and body with small tiny brownish black spots; second dorsal rays light brown; and pectoral fin base with many small melanophores, fin membrane with melanophores on basal region.

Description

Body very slender, cylindrical anteriorly and somewhat compressed posteriorly (all morphometric data is shown in Table 1 View TABLE 1 ).

Head flat and depressed. Cheek slightly fleshy. Eye small. A horizontal dermal fold with papillae row on upper part of cheek and below orbit. A dermal projection present on rear corner of orbit.

Snout flat and short. Anterior nasal opening as a protruded, horizontal short tube and posterior nasal opening as a round hole. Interorbital region wide. Mouth oblique and large, maxillary extending to vertical of anterior margin of orbit. Lower jaw more prominent compared to upper jaw. Teeth rather minute, with 4–5 rows of tiny conical teeth where outer rows larger in both jaws. Tongue somewhat pointed, but anterior tip bilobed. Gill opening rather restricted, extending merely slightly below lower margin of pectoral base. Anus located in posterior half of body. Vertebral count 16 + 20 = 36.

Fins. D2 I/11, A I/12, P 18. D1 absent. D2 with middle one third portion of rays longest. A shape similar to D2. Both first spines in D2 and A relatively short. A origin in front of D2 origin. D2 origin inserted vertically between 1st and 2nd branched rays of A. Both rear tip of D2 and A far from procurrent rays of C when depressed. P rounded and its length much shorter than postorbital length. P with one free soft ray on upper margin very near upper basal region. C elliptical. V as a round sucking disc with complete frenum and rather small.

Scales. Both body and head entirely naked without any scales.

Head lateral-line system ( Figure 8 View FIGURE 8 )

Head canals: whole head lacking any canal and head pores.

Sensory papillae: a series of infraorbital sensory papillae, typically representing a longitudinal pattern. Row a long and extending to snout which upward to surrounding eye diameter in interorbital region. Row b rather long starting above middle of dermal ridge, its length about two times eye diameter. Row c mainly below dermal fold and long. A single cp located below rear Row c. Row d shorter than row c. Row f paired only as two papillae. Opercle with three rows ot, os, and oi. Rows oi and ot well separated. Rows z as single vertical row. Other papillae are shown in detail in Figure 5 View FIGURE 5 .

Coloration when fresh

Body and head light creamy yellow to yellowish brown background. Head and body with small tiny brownish black spots. Second dorsal fin translucent with all rays light brown. Anal fin translucent all rays creamy yellow or pale yellow. Pectoral fin base with many small melanophores, pectoral fin membrane translucent with small melanophores merely on basal region. Caudal fin light brown with small light marks posteriorly. Pelvic fin translucent and creamy white.

Distribution

Till present, this species has only been found in the coastal region of New Taipei City in Taiwan. It is a coastal species on the island. There is a high possibility that it is a species endemic to Taiwan.

Etymology

The specific name, newtaipeiensis , refers to the type locality from New Taipei City in Taiwan.

Remarks

Luciogobius newtaipeiensis sp. nov. is quite similar to Luciogobius guttatus Gill, 1859 due to the similarities in the number of pectoral fin rays and the presence of one upper free ray, more so than any other congeneric species.

However, Luciogobius newtaipeiensis sp. nov. can be well distinguished from Luciogobius guttatus by the following features: (1) second dorsal fin rays I/11 vs. modally I/12; (2) anal fin rays I/12 vs. modally I/13; (3) vertebral count: 16 + 20 = 36 vs. 17 + 21 = 38; (4) an upper dermal projection on orbit: present in male vs. none; and (5) specific coloration: pectoral fin membrane with less brown spotted merely extending around anterior 1/3 of fin membrane vs. rather high black spotted extending beyond middle of fin membrane.

Since L. guttatus is believed to be an endemic species to Japan, it is possible that some fish guide books in Taiwan may have misidentified this new species as the so-called “ Luciogobius guttatus ”.