''Microphysogobio exilicauda'' is a species of freshwater

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...

belonging to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Gobionidae Gobioninae is a monophyletic family of Eurasian cyprinoid fishes. This is a species rich clade which, as a subfamily of the Cyprinidae was divided into five tribes: Gobionini, Pseudogobionini, Hemibarbini, Coreiini, and Sarcocheilichthyini. T ...

, the gudgeons. This fish is found in the

Pearl River The Pearl River (, or ) is an extensive river system in southern China. "Pearl River" is often also used as a catch-all for the watersheds of the Pearl tributaries within Guangdong, specifically the Xi ('west'), Bei ('north'), and Dong ( ...

basin in

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

. All of the specimens were collected in the Pearl River basin in Guangdong Province, China, in 1976. It is sometimes considered an ambiguous synonym of '' Microphysogobio chenhsienensis''. Differs from ''M. chenhsienensis'' in that it has a thin (vs. stouter) caudal peduncle (depth 6.8–7.8 vs. 9.0–10.5 percent of SL; length 17.1–19.5 vs. 13.9–16.3 percent of SL); and a narrower (vs. greater) interorbital gap than eye. The body is elongated, anteriorly subcylindrical, and posteriorly compressed, with the greatest body depth at the dorsal fin origin and the smallest caudal-peduncle depth directly anterior to the caudal-fin base. From the snout tip to the dorsal-fin origin, the dorsal body profile is slightly convex or straight; from there to the caudal-fin base, it is slightly concave. From the snout tip to the pectoral-fin insertion, the ventral profile is flat; from then to the anal-fin origin, it is convex, then slightly concave from the anal-fin origin to the caudalfin base. Anus is located slightly closer to the insertion of the pelvic fin than to the origin of the anal fin. Slender and tightly compressed caudal peduncle. The head is small, and the depth of the body is approximately equal to or shorter than the depth of the head. When viewed from the side, the snout is bluntly rounded, with a shallow transverse notch across the tip in front of the nostrils. Large, dorsolaterally positioned eye that is practically in the centre of the skull. Interorbital space is somewhat concave, narrow, and has a breadth that is smaller than the diameter of the eye. Nostrils are closer to the eye's anterior edge than to the tip of the snout. Maxillary barbels are rooted at the base of the external surface of the confluence of the upper and lower lips at the mouth's corner, and are shorter than half the diameter of the eye. Mouth is inferior and transverse, with a fissure at the corner of the mouth that bends somewhat backward.

References

exilicauda Freshwater fish of China Fish described in 2013 {{Gobioninae-stub