The lefteye flounder family Bothidae (Order Pleuronectiformes) of Taiwan
Author
Amaoka, Kunio
Author
Ho, Hsuan-Ching
text
Zootaxa
2019
2019-12-04
4702
1
155
215
journal article
24734
10.11646/zootaxa.4702.1.18
d2251320-5eef-450d-9703-2d2004e4962b
1175-5326
3562779
9108DB7D-3722-4F5C-BD76-F387E813BECB
Crossorhombus valderostratus
(
Alcock, 1890
)
Victory bluespotted flounder;
xühḃľ
Figures 6
C–F;
Table 6
Rhomboichthys
valde-rostratus
Alcock, 1890:435
(
Type
locality:
Sri Lanka
).
Crossorhombus valde-rostratus
:
Norman, 1927:28
.
Crossorhombus valderostratus
:
Hensley & Randall, 1993:1125
.
Crossorhombus kobensis
:
Shen, 1983:18
, fig. 23.
Specimens examined.
NMMB-P22286
(
5 males
,
4 females
, 51.3–70.7), Ke-tzu-liao,
28 Mar. 2015
; NMMB- P25675 (
6 females
, 65.2–73.3)
,
NMMB-P25712
(
3 males
, 60.1–70.5), Ke-tzu-liao,
27 Jun. 2016
. More specimens deposited in
NMMB-P.
Diagnostic features.
D 82–88; A 62–68; P 10–12; C 2+13+2=17; LLs 46–55; GR 0(1)+6–7=6–7; vert. 10+23– 25=33–35.
Body short and deeply ovate, greatest depth slightly before middle part of body (54.4–63.2% SL). Head much shorter than half of body depth (24.5–27.4% SL); upper profile of head with deep concavity anterior of upper margin of lower eye; head profile steep, almost vertical in mature males, less steep in females and juveniles. Snout much shorter than eye diameter. Rostral spine on tip of snout, sharp and strong in males, absent in females and juveniles. Eyes diameter slightly shorter than upper jaw. Small orbital spines at anterior margin of both eyes in males, absent in females and juveniles. Interorbital space deeply and widely concave, its width wider in males than in females and juveniles.
Mouth small and lipped, upper-jaw length 6.8–7.9% SL; maxilla extending to slightly beyond anterior margin of lower eye. Teeth on upper jaw biserial, those on outer series larger and more widely spaced than those on inner series; teeth on lower jaw uniserial, similar to inner teeth of upper jaw. Gill rakers on lower limb short and blunt, not serrate; absent on upper limb. Scales on ocular side small, ctenoid with long ctenii on posterior margin; scales on blind side cycloid. Pectoral-fin rays on ocular side filamentous in males, pectoral-fin length 32.6–41.9% SL in males, 19.7–24.7% SL in females.
Coloration.
Ocular side of body dark to light brown with many dark spots and obtuse dark blotches; faint large dark blotch on curve and middle of straight section of lateral line; surface of eyes with many dark spots; margins of dorsal and anal fins not dark; blind side of body in males with distinct deep-bluish pattern in horizontal V-shape, uniformly whitish in females.
Size.
Reaching
104 mm
SL in
Taiwan
, up to
121 mm
SL known from
Kenya
(
Hensley and Randall 1993
).
Distribution.
Southern
Taiwan
; widespread in Indian and West Pacific oceans (
Amaoka, 2016
).
Remarks.
Specimens more than about
60 mm
SL exhibit a distinct sexual dimorphism in respect to the interorbital width, presence of rostral and orbital spines at both eyes, the pectoral-fin length on the ocular side and body coloration on the blind side.
Crossorhombus valderostratus
very closely resembles
C. howensis
from Lord Howe Islands and
Taiwan
, but it differs from latter in having longer pectoral fins on the ocular side in males (32.6–41.9% SL, vs. 27.8–31.8), and a filamentous second ray of the pectoral fin.Also,
C. valderostratus
inhabits in deeper water than
C. howensis
.