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| Henicorhynchus siamensis (Sauvage, 1881) in Ciccotto & Page, 2020. ปลาสร้อยขาว || DOI: 10.1643/CI-19-304 |
Abstract
The Southeast Asian cyprinid genus Henicorhynchus has a complicated taxonomic history due to morphological similarities with other genera and among species within the genus itself. Henicorhynchus and its constituent species are herein revised based on morphological examinations of over 1,000 specimens with a particular emphasis on oromandibular structures. Five species are now recognized in the genus. Henicorhynchus entmema and H. caudimaculatus are senior synonyms of H. lobatus and H. lineatus, respectively. Henicorhynchus caudiguttatus is removed from synonymy with H. caudimaculatus. A revised diagnosis of the South Asian cyprinid genus Gymnostomus, previously considered a senior synonym of Henicorhynchus, is also provided.
Henicorhynchus Smith, 1945
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.
Henicorhynchus caudiguttatus (Fowler, 1934)
Spotted Mud Carp
Crossocheilus caudiguttatus Fowler, 1934:137, fig. 103.
Type locality: Thailand, Chieng Mai. Holotype: ANSP 58452.
Diagnosis.— A member of Henicorhynchus distinguished from other members of the genus (Table 1) by the following combination of characters: mouth terminal, strongly oblique (35–45° to midline of body); maxillary barbels present; edge of rostral cap straight, without medial indent; flank immaculate, without longitudinal stripes; caudal peduncle with small brown spot at medial insertion of caudal fin; caudal fin with scattered brown spots in larger specimen (holotype, 59.8 mm SL).
Distribution.— Henicorhynchus caudiguttatus is known only from the type locality of Chiang Mai in northern Thailand (Fig. 9A).
Henicorhynchus caudimaculatus (Fowler, 1934)
Striped Mud Carp
Tylognathus caudimaculatus Fowler, 1934:133, figs. 89–90.
Type locality: Thailand, Chiang Mai. Holotype: ANSP 58332.
Cirrhinus lineatus Smith, 1945:163, fig. 25. Type locality: Thailand, Lam Ton Lang, a tributary of Menam Sak. Holotype: USNM 107960.
Cirrhinus caudimaculatus—Roberts, 1997.
Cirrhinus lineatus—Roberts, 1997.
Gymnostomus caudimaculatus—Kottelat, 2013.
Gymnostomus lineatus—Kottelat, 2013.
Diagnosis.— A member of Henicorhynchus distinguished from other members of the genus (Table 1) by the following combination of characters: mouth subterminal, weakly oblique to nearly horizontal (less than or equal to 20° to midline of body); maxillary barbels present; edge of rostral cap straight, without medial indent; longitudinal stripes on flanks in most specimens, particularly larger individuals; caudal peduncle with small brown spot at medial insertion of caudal fin in smaller specimens; caudal fin mostly clear, with scattered melanophores; pectoral, pelvic, and anal fins hyaline in life.
Distribution.— Henicorhynchus caudimaculatus is distributed in the Chao Phraya basin in Thailand and the Mekong basin in Cambodia, Lao PDR, and Thailand (Fig. 9B).
Henicorhynchus entmema (Fowler, 1934)
Notched Mud Carp
Tylognathus entmema Fowler, 1934:134, figs. 101–102.
Type locality: Thailand: Bangkok: Silom canal. Holotype: ANSP 59092.
Cirrhina sauvagei Fang, 1942:168. Type locality: Mekong, southeastern Asia. Syntypes: MNHN 8598 [8].
Crossocheilus thai Fowler, 1944: 49, 1 fig. Type locality: Thailand, Bangkok. Holotype: ANSP 71336.
Henicorhynchus lobatus Smith, 1945:257, fig. 49. Type locality: Thailand: Chiang Rai Province: Mekok River near Chiang Rai. Holotype: USNM 119490.
Cirrhinus lobatus—Roberts, 1997.
Gymnostomus lobatus—Kottelat, 2013.
Diagnosis.— A member of Henicorhynchus distinguished from other members of the genus (Table 1) by the following combination of characters: mouth subterminal, weakly oblique to nearly horizontal (less than or equal to 20° to midline of body); maxillary barbels almost always present (rarely absent); edge of rostral cap with distinct medial indent; flank immaculate, without longitudinal stripes; caudal peduncle immaculate or with brown to black spot at medial insertion of caudal fin; caudal fin mostly clear, with scattered melanophores; pectoral, pelvic, and anal fins hyaline in life.
Distribution.— Henicorhynchus entmema is distributed in the Chao Phraya and Mae Klong basins in Thailand and the Mekong basin in Cambodia, Lao PDR, Thailand, and Vietnam (Fig. 9C).
Henicorhynchus ornatipinnis (Roberts, 1997)
Red-finned Mud Carp - ปลาสร้อยครีบส้ม
Cirrhinus ornatipinnis Roberts, 1997:195, fig. 13.
Type locality: Thailand, roadside ditch on highway 24 at km 150 marker, 179 km by road east of Nakorn Ratchasima. Holotype: CAS 91756.
Gymnostomus ornatipinnis—Kottelat, 2013.
Diagnosis.— A member of Henicorhynchus distinguished from other members of the genus (Table 1) by the following combination of characters: mouth subterminal, weakly oblique to nearly horizontal (less than or equal to 20° to midline of body); maxillary barbels absent; edge of rostral cap straight, without medial indent; flank immaculate, without longitudinal stripes; caudal peduncle immaculate, without spot; anterior ¾ of caudal fin dusky, posterior ¼ hyaline; pectoral, pelvic, and anal fins red or orange in life.
Distribution.— Henicorhynchus ornatipinnis is native to temporary habitats, including roadside canals, of the middle portion of the Mekong River basin in Thailand (Roberts, 1997; Fig. 9A). It is also reported from slow-flowing lotic habitats in Lao PDR (Kottelat, 2001).
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| Henicorhynchus siamensis, UF 191421, live, 51.5 mm SL. Photo by Z. Randall (FLMNH). |
Henicorhynchus siamensis (Sauvage, 1881)
Siamese Mud Carp - ปลาสร้อยขาว
Morara siamensis Sauvage (ex Bleeker), 1881:164, 187, pl. 6 fig. 2.
Type locality: Thailand, Bangkok. Syntypes: MNHN 0000-1839 (4).
Tylognathus siamensis de Beaufort, 1927:5. Type locality: Thailand: Chiang Rai Province, Payao Swamp. Holotype: ZMA 112.583.
Tylognathus brunneus Fowler, 1934:131, figs. 87–88. Type locality: Thailand, Chiang Mai. Holotype: ANSP 58369.
Cirrhinus marginipinnis Fowler, 1937:173, figs. 108–109. Type locality: Thailand, Pitsanulok. Holotype: ANSP 68069.
Cirrhinus siamensis—Roberts, 1997.
Gymnostomus siamensis—Kottelat, 2013.
Diagnosis.— A member of Henicorhynchus distinguished from other members of the genus (Table 1) by the following combination of characters: mouth terminal, strongly oblique (35–45° to midline of body); maxillary barbels absent; edge of rostral cap straight, without medial indent; flank immaculate, without longitudinal stripes; caudal peduncle immaculate, without spot; caudal fin mostly clear, with scattered melanophores; pectoral, pelvic, and anal fins hyaline in life (Fig. 9).
Distribution.— Henicorhynchus siamensis is distributed in the Bang Pakong, Chao Phraya, Mae Klong, and Phetchaburi basins in Thailand as well as the Mekong basin in Cambodia, Lao PDR, Thailand, and Vietnam (Fig. 9D).
Patrick J. Ciccotto and Lawrence M. Page. 2020. Revision of the Genus Henicorhynchus, with A Revised Diagnosis of Gymnostomus (Cyprinidae: Labeoninae). Copeia. 108(3), 485-502. DOI: 10.1643/CI-19-304
