Henicorhynchus Smith 1945
Creators: name: Ciccotto, Patrick J.
name: Page, Lawrence M.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Cypriniformes
Cyprinidae
Henicorhynchus

description: Henicorhynchus Smith, 1945   
Figures 1–8  
 Henicorhynchus Smith, 1945:256. Type species: Henicorhynchus lobatus Smith, 1945, by original designation (also monotypic).   
 Synonym of Cirrhinus Oken, 1817 — Roberts, 1997.   
 Synonym of Gymnostomus Heckel, 1843 — Kottelat, 2003.   
  Diagnosis.— Henicorhynchus  is distinguished from other labeonin genera by the following combination of characters: 1) mouth transverse, either terminal or subterminal; 2) rostral cap covering most of upper lip, in some individuals strongly overhanging medial portion; 3) edge of rostral cap smooth or with single medial indent; 4) shallow lateral groove extending obliquely anteriorly from corner of mouth to snout; 5) upper lip adnate to exposed surface of upper jaw and continuous with lower lip around corner of mouth, not covering entire upper jaw; 6) edge of upper lip smooth, without papillae; 7) maxillary barbels present or absent, but rostral barbels always absent; 8) lower lip firmly attached to lower jaw and without fleshy medial cushion or lobe; 9) 8 branched dorsal-fin rays; 10) humeral region immaculate, without distinct blotch.   
 Description.— Mouth terminal, strongly oblique (35–458 to midline of body), or subterminal, weakly oblique to nearly horizontal (less than or equal to 208 to midline of body). Rostral cap covering most of upper lip; edge with papillae, either straight or with distinct medial notch; tubercles infrequently present on tip of snout. Upper lip thin, fused with upper jaw; continuous with lower lip around corner of mouth; edge with papillae. Lower jaw slightly arched, cornified at edge. Lower lip thin, adnate to jaw; postlabial grooves separating lateral aspects from center. Maxillary barbels present or absent; if present, small and barely exposed at corner of mouth.   
 Dorsal profile slightly arched; deepest at dorsal-fin origin; ventral profile slightly convex. Head short, longer than wide; snout conical, rounded anteriorly; eyes lateral. Dorsal-fin origin anterior of pelvic-fin origin. Pectoral fins positioned ventrally, reaching approximately to ł distance from origin to = pelvic-fin origin when adpressed. Pelvic fins reaching 2 3 distance = to just anterior to anus when adpressed. Anal fin reaching 2 3 distance or to base of caudal fin when adpressed. Axillary pelvic lobes well developed. Dorsal and anal fins slightly concave to falcate; pectoral and pelvic fins triangular. Caudal fin deeply forked with pointed lobes approximately equal in length.   
 Dorsal fin with 3 simple and 8 branched rays; anal fin with 3 simple and 5 branched rays; pelvic fin with 1 simple and 8 branched rays; pectoral fin with 1 simple and 13–16 branched rays; caudal fin with 10 þ 9 principal rays, 9 þ 8 branched. Body entirely scaled; scales well developed. Lateral-line scales and pored scales on caudal fin 31–35 þ 1– 4; predorsal scales 8–12; scale rows above lateral line 5 (rarely 6); scale rows below lateral line 4 –5 (rarely 6); scale rows between lateral line and pelvic-fin origin 4 (rarely 5); circumpeduncular scales 20.   
  Comparisons.— Henicorhynchus  is most similar to Gymnostomus (see generic account below), several species currently placed in Cirrhinus, and Lobocheilos. Henicorhynchus is distinguished from Gymnostomus by a rostral cap with a straight edge or single medial indent (vs. rostral cap with fimbriae in Gymnostomus) and the absence (vs. presence) of rostral barbels. Henicorhynchus is distinguished from species of Cirrhinus sensu Kottelat (2013), including C. cirrhosus; C. jullinei Sauvage, 1878; C. microlepis Sauvage, 1878; C. molitorella; and C. prosemion (Fowler, 1934), by having 8 branched dorsal-fin rays (vs. 9 or more in the aforementioned species of Cirrhinus). Cirrhinus cirrhosus, C. jullieni, C. molitorella, and C. prosemion all have rostral barbels (vs. rostral barbels absent in Henicorhynchus). In both C. cirrhosus and C. microlepis, the upper lip covers the entirety of the upper jaw (vs. upper lip adnate to upper jaw). In C. molitorella and C. prosemion, the upper lip possesses distinct papillae along the edge (vs. smooth edge to upper lip in Henicorhynchus). Henicorhynchus is distinguished from ‘ Cirrhinus ’ inornatus and ‘ C.’ rubirostris (originally described in Cirrhinus by   
 Roberts [1997] and later placed in Gymnostomus by Kottelat [2013]; see discussion below about generic classification for these two species) by an upper lip adnate to the upper jaw and a cornified sheath on the upper jaw (vs. an upper lip that covers the entire upper jaw), the absence (vs. presence) of a post-oral groove, 8 (vs. 9) branched dorsal-fin rays, and an immaculate humeral region (vs. supracleithral blotch present). Henicorhynchus is distinguished from Lobocheilos by having the lower lip firmly attached to the lower jaw (vs. lower lip with a fleshy medial lobe that is free anteriorly and laterally).   
  Remarks.— Henicorhynchus  is a member of the cyprinid subfamily Labeoninae based on the ventrally expanded rostral fold, the presence of a superficial posterior labial fold, and the presence of a vomero-palatine organ (Stiassny and Getahun, 2007). The diagnostic characters of Labeoninae reported by Reid (1982), including a terete process on the basioccipital and the direct contact between the neural complex of the Weberian apparatus and the supraoccipital region, could not be examined in specimens on loan to us, but were reported present in H. siamensis by Stiassny and Getahun (2007). Additionally, an incised border on the first anal-fin pterygiophore was observed in radiographs of the holotypes of H. entmema (Fowler, 1934; ANSP 59092) and H. ornatipinnis (Roberts, 1997; CAS 91756), and was observed in H. siamensis (Sauvage, 1881) by Stiassny and Getahun (2007), who reported this character as an additional diagnostic character of Labeoninae. Several molecular phylogenies place Henicorhynchus within Labeoninae (Wang et al., 2007; Yang et al., 2012; Zheng et al., 2012).   
 The common name ‘‘mud carp’’ is used for several species of Henicorhynchus and C. molitorella, which is often more specifically referred to as the Chinese Mud Carp. We retain the use of mud carp in the common names of species of Henicorhynchus.
description: Published as part of Ciccotto, Patrick J. & Page, Lawrence M., 2020, Revision of the Genus Henicorhynchus, with a Revised Diagnosis of Gymnostomus (Cyprinidae: Labeoninae), pp. 485-502 in Copeia 108 (3) on pages 485-502, DOI: 10.1643/ci-19-304, http://zenodo.org/record/13628562