Microdous amblyrhynchos, Hu & Lan & Li, 2023
|
publication ID |
https://dx.doi.org/10.3897/zookeys.1153.97139 |
|
publication LSID |
lsid:zoobank.org:pub:3CA1ADD3-91AF-4169-B656-66F02CE797D2 |
|
persistent identifier |
https://treatment.plazi.org/id/2C35228B-6C4A-4D19-B8EC-C0E03CB2D67E |
|
taxon LSID |
lsid:zoobank.org:act:2C35228B-6C4A-4D19-B8EC-C0E03CB2D67E |
|
treatment provided by |
|
|
scientific name |
Microdous amblyrhynchos |
| status |
sp. nov. |
Microdous amblyrhynchos sp. nov.
Figs 2 View Figure 2 , 3 Blunt-snout small-toothed sleeper, Dùn Wěn Xì Chǐ Yoù, 钝吻细齿䱂 (Chinese) View Figure 3
Type material.
Holotype. SOU1801010-7 (CL3084-7) (Fig. 2 View Figure 2 ), male, 74.9 mm standard length (SL), obtained from an unnamed stream of a tributary of the Hongshui River, upper reaches of the Xijiang River of the Pearl River basin; Lihong Village (24°26.21'N, 106°26.72'E; c. 870 m a.s.l.), Yuhong Town, Lingyun County, Baise City, Guangxi, China (Fig. 1 View Figure 1 ); collected using fish trap by J.H. Lan, May 2020.
Paratypes. SOU1801010-8 (CL3084-8), female, 66.9 mm SL; SOU1801010-1 (CL3084-1), male, 69.8 mm SL; SOU1801010-2(CL3084-2), male, 63.2 mm standard length; SOU1801010-3 (CL3084-3), male, 76.2 mm SL. Sampling data same as for the holotype.
Diagnosis.
Microdous amblyrhynchos sp. nov. can be distinguished from the only congener M. chalmersi by the following character states: snout blunt, snout length/head length ratio 0.26-0.28, mean 0.27 (vs. pointed, snout length/head length ratio 0.28-0.32); eye large, but not protruding outward, interorbital width larger than eye diameter, interorbital width/head length ratio 0.22-0.27,mean = 0.25 (vs. large and protruding eye, interorbital width equal to or smaller than eye diameter, interorbital width/head length ratio 0.11-0.12) (Fig. 4 View Figure 4 ).
Description.
Morphometric and meristic data for the holotype and paratypes are presented in Table 1 View Table 1 . The maximum standard length (SL) was 76.2 mm.
First dorsal fin rays VII or VIII; second dorsal fin rays I/9-10; anal fin rays I/8-9; pectoral fin rays 15; pelvic fin rays I/5; caudal fin rays 15; longitudinal scale rows 40-41; transverse scale rows 13; predorsal scales 21-24; gill rakers 4+9; vertebrae 34 (16+18).
Body stout, slightly compressed posteriorly. Head large, slightly depressed. Eye large, located in anterior half of head, not protruding outward. Several rows of tiny conical teeth on both jaws. Tiny, slender, teeth-like dermal projections in vomerine region (Fig. 5A View Figure 5 ). Gill opening extending to under anterior part of eye. Cephalic sensory canals complete (Fig. 6 View Figure 6 ). Urogenital papilla distinct, rest behind the anus opening (Fig. 7 View Figure 7 ).
Posterior tip of dorsal fin reaching origin of second dorsal fin when depressed. Second dorsal fin ends distinctly anterior of origin of caudal fin. Caudal fin and pectoral fin large, elliptical. Pelvic fins well separated, rear tip not reaching anus. Interopercle and subopercle naked. Ctenoid scales on dorsal and lateral side of body, ventral side of body posterior to anus and opercle, transforming ctenii present. Small cycloid scales on predorsal area, cheek, nape, preopercle, base of the pectoral fin, breast and abdomen.
Coloration in life. Head black and dark brown with black dots on cheek. Body side yellowish, several irregular dark patches and orange dots on the side. Back dark brown. Unpaired fins possessing several inconspicuous stripes of dark spots and white edge. Pectoral fins and pelvic fins transparent and dusky. An irregular black fleck on upper part of base of pectoral fin. Ventral side of abdomen pale, with dull and inconspicuous dark patches. Urogenital papilla dark brown (Fig. 3A View Figure 3 ).
Coloration preserved. Head dark brown with black dots on the cheek. Body side brown, orange dots absent. Back brown. Irregular black fleck on upper part of base of pectoral fin dull and inconspicuous. Ventral side of abdomen light brown. Urogenital papilla whitish (Fig. 3B View Figure 3 ).
Sexual dimorphism. Urogenital papilla elongate with a wide base, tapering and with a narrow tip in male; truncated in female (Fig. 7 View Figure 7 ).
Cephalic sensory canals system. Anterior extension in front of interorbital with three pairs of pores A, B and C, and a single interorbital pore D. A pair of pores E lateral to pore D. Lateral section of oculoscapular canal with a series of seven pairs of pores: F to L (terminal). Preopercular canal extending to ventral side of preopercle, with five pairs of pores: M (dorsal) to Q (ventral) (Fig. 6 View Figure 6 ).
Cephalic sensory papillae. Neuromast numerous, small and densely set in mostly longitudinally arranged rows (Fig. 6 View Figure 6 ).
Biology.
Mircodous amblyrhynchos can be found in small creeks or rivers with slow moving, clear water and rocky bottom. Some remains of chitin exoskeleton of crustaceans were found in the anus opening of the holotype, suggesting that M. amblyrhynchos is carnivorous. The male’s head would turn black with several orange dots on the body sides during their spawning seasons.
Etymology.
This species is named for its blunt snout distinguishing it from M. chalmersi . The species name derives from Greek ambly meaning dull or blunt and rhynchos meaning snout.
Phylogenetic analysis.
The COI tree with three individuals of M. amblyrhynchos and representative species of all available Odontobutidae genera except for Terateleotris is shown in Fig. 8 View Figure 8 . Rhyacichthys aspro Valenciennes, 1837 was used as the outgroup following Li et al. (2018). All genera of Odontobutidae were monophyletic in the tree. All M. amblyrhynchos specimens formed a clade distinct from M. chalmersi . The p-distance between M. amblyrhynchos and M. chalmersi was 10.7% (Suppl. material 1), suggesting that M. amblyrhynchos is a distinct species of the genus Microdous .
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.