Paratanakia fulvidorsalis sp. nov.

(ḃüƋŝ)

(Figs. 1–3)

Material examined

Holotype.— NTOUP-2010-10-301, 53.8 mm SL, male, Dashi, Taoyuan City, Tanshuei River basin, Taiwan, coll. I-S. Chen et al., 15 Oct. 2010.

Paratypes.— NTOUP-2010-10-302, 4 specimens, 40.2–50.1 mm SL, collection date and other data same as above holotype.

Diagnosis

Paratanakia fuvlidorsalis n. sp. which endemic in Taiwan can be well distinguished from other congeners by the following unique combination of features: (1) fin ray counts: dorsal fin rays 3, 8; anal fin rays 3, 10; pectoral fin rays modally 1, 12; (2) squamation: lateral-line scales modally 34; and (3) specific color pattern: dorsal fin gray with a broad shiny creamy yellow to orange yellow stripe, and with a thin grayish black margin in male.

Description

Dorsal fin rays 3, 8. Anal fin rays 3, 10. Pectoral fin rays 1, 12. Pelvic fin rays 1, 7. Lateral-line scales 33–34 (modally 34). Transverse scales 10. Pre-dorsal scales 12–13 (modally 13). Vertebral count 4+29=33 (n=5).

All body proportion listed in Table 1. Body compressed and roughly spindle shaped. The highest position of dorsal line located at the anterior margin of dorsal fin base. Head small, snout slightly prominent, tip slightly rounded. Mouth small, a pair of barbels at mouth corner. Eye large and located on lateral side of head. Belly slightly rounded in both sexes. Lateral-line complete and running slightly downward abruptly above the anus and along the ventral profile into middle of caudal fin base. Body covered with moderate-sized cycloid scales. Belly from inter-pectoral fin basal region extending backward to anal fin anterior base, always covered with cycloid scales.

Pectoral fin almost reaching anterior margin of pelvic fin when compressed in both sexes. Pelvic fin slightly rounded. Anterior margin of anal fin inserted below second branched ray of dorsal fin. The length of dorsal fin in male is distinctly longer than in female when compressed. Caudal fin deeply forked and rear margin of caudal fin lobe rounded. Two patches of turbucles appeared on snout in adult male, absent in female.

Coloration while fresh (Figs. 1–3)

Upper areas of head and body generally pale yellowish. Scales on upper area of body side with gray margin. Belly silver white. A distinct longitudinal blue stripe on posterior half of body, starting from caudal fin base and extending forward to the position on vertical above pelvic fin base. Middle belly from inter-pectoral region to anterior margin of anal fin is silver light blue in mature male, but silver white in female. Eye grayish white with light pinkish around the pupil in mature male, but grayish white in female. Caudal peduncle pinkish in male.

Color of all fins in male and female is completely different. In male, dorsal fin gray with a broad shiny creamy yellow to orange yellow stripe, and with a thin grayish black margin. Anal fin gray with yellowish to pinkish orange stripe, and with broad grayish black margin. Pectoral fin pale yellow. Pelvic fin pale white to grayish. Caudal fin yellow, central area with a longitudinal black stripe. In female, dorsal fin usually uniformly grayish, but some individuals with indistinct pale white stripe. Anal fin gray with yellowish to pinkish orange stripe, and with grayish black margin. Pectoral fin cream yellow. Pelvic fin grayish white. Caudal fin creamy yellow, central area with a broad longitudinal black bar.

Distribution. Currently known only from the lower reaches of Tanshuei River basins with very limited locality.

Etymology. The specific name, “ fulvodorsalis ” refers to the specific feature in adult male- “yellow (fulvus)” + “dorsal fin (dorsum)”.

Remarks

Among the member of the genus, P. fulvidorsalis sp. nov. is more similar to P. chii than any other species. However, P. fulvidorsalis sp. nov. can be well distinguished from P. chii by following features (meristic comparison seen in Table 2): (1) dorsal fin rays: 3, 8 vs. 3, 9; (2) anal fin rays: 3, 10 vs. modally 3, 11; and (3) dorsal fin pattern: a creamy yellow to orange yellow horizontal stripe in male vs. modally snow white in male. The great mitogenetic differentiation is also detected by Chen et al. (unpublished data).