[Ichthyology • 2024] Vexillichthys gen. nov. • A New Genus for the Blackfin Sucker, Thoburnia atripinnis (Cypriniformes: Catostomidae)

Vexillichthys Armbruster, new genus
Vexillichthys atripinnis (Bailey 1959) 

in Armbruster, 2024. 

 DOI: 10.11646/zootaxa.5536.2.8

Abstract

Thoburnia atripinnis is more closely related to Hypentelium (hogsuckers) than it is to other Thoburnia, and its presence in the Barren River of Kentucky is disjunct from that of true Thoburnia. Its unique morphology is unlike that of the easily recognized hogsuckers, making placement of the species within Hypentelium untenable; thus, a new genus is described. The new genus can be separated from all other catostomids by the presence of thin, black, prominent stripes on the body, a large black mark on the anterodist al portion of the dorsal fin, presence of pads ventrally on the leading portion of the pectoral fin, lateral laminae of the dermethmoid angled anteriorly, and the base of the lateral ethmoid narrow.

Pisces, Hypentelium, Moxostoma, Thoburnini, Taxonomy

Live specimens of Vexillichthys n. gen. atripinnis.
A. young in typical coloration (90 mm SL, Salt Lick Creek at Bugtussle Road crossing, Monroe Co., KY, ...) and
B. nuptial specimen, probably female (147 mm SL, Long Hungry Creek, at KY 1333 crossing, Allen Co., KY, ...). Specimens uncataloged.

Photos by M. Thomas.

Vexillichthys Armbruster, new genus

Type species. Moxostoma (Thoburnia) atripinne Bailey 1959

Diagnosis. Vexillichthys can be separated from all other Catostomids by the presence of well-developed, thin, black stripes on the body and a large, black mark on the anterodistal portion of the dorsal fin. Members of Hypentelium and Thoburnia may have stripes, but the stripes are faint, and the dorsal saddles are darker than the stripes (vs. the stripes darker than the saddles in Vexillichthys). Hypentelium does have dark marks in the dorsal fin, but the fin has bands or blotches instead of a single, large, black area at the anterodistal portion of the fin and the remainder of the fin hyaline. Vexillichthys can be further separated from Thoburnia by lacking a rust-colored, wide lateral stripe. Minytrema also has dark stripes, but these are composed of distinct ...

Etymology. From the Latin vexillum for flag and the Greek ichthys for fish. The dorsal fin has a flaglike pattern and the approximately thirteen alternating dark and light stripes are like the flag of the United States of America. Gender masculine.

Jonathan W. ARMBRUSTER. 2024. A New Genus for the Blackfin Sucker, Thoburnia atripinnis (Cypriniformes: Catostomidae).  Zootaxa. 5536(2); 325-335. DOI: doi.org/10.11646/zootaxa.5536.2.8

 

[Ichthyology • 2024] Opsariichthys iridescens • A New Species of Opsariichthys (Cypriniformes: Xenocyprididae) from Southeast China

Opsariichthys iridescens Peng, Zhou & Yang,

in Peng, Zhou, Gao et Yang, 2024.  

虹彩马口鱼  ||  DOI: 10.3897/zookeys.1214.127532

Abstract

Opsariichthys iridescens sp. nov. is described from the Qiantang and Oujiang rivers in Zhejiang Province and a tributary of the Yangtze River adjacent to the Qiantang River. It is distinguished from congeners by the following combination of morphological features: no obvious anterior notch on the tip of the upper lip; 45–52 lateral-line scales; 18–21 pre-dorsal scales; two rows of pharyngeal teeth; a maxillary extending to or slightly beyond the vertical anterior margin of the orbit in adult males; a pectoral fin extending to the pelvic fin in adult males; nuptial tubercles on the cheeks and lower jaw of males, which are usually united basally to form a plate; uniform narrow pale pink cross-bars on trunk and two widening significantly on caudal peduncle. Its validity was also supported by its distinct Cyt b gene sequence divergence from all congeners and its monophyly recovered in a Cyt b gene-based phylogenetic analysis.

Key words: Cytochrome b, morphology, opsariichthine, phylogenetic analysis, principal component analysis (PCA), taxonomy

Family Xenocyprididae Günther 1868

Genus Opsariichthys Bleeker, 1863

Opsariichthys iridescens sp. nov. A live male B live female;
Opsariichthys bidens C live male D live female;
Opsariichthys evolans E live male F live female.

 Opsariichthys iridescens Peng, Zhou & Yang, sp. nov.

Diagnosis: The new species, Opsariichthys iridescens sp. nov. can be clearly distinguished from its two sympatric congeners in the Qiantang River and nearby geographic regions (Tables 3, 4). It can be distinguished from O. evolans by the following features: (1) lateral-line scales 45–52 (vs 42–45); (2) scales above lateral-line nine or ten (vs 8); (3) pre-dorsal scales 18–21 (vs 15–17); (4) two rows of pharyngeal teeth (vs 3 rows); (5) maxillary extending to or slightly beyond the vertical of anterior margin of orbit in adult male (vs never extending to the vertical of anterior margin of orbit); (6) pectoral fin extending to pelvic fin in adult male (vs extending far beyond origin of ventral fin); (7) almost uniform narrow pale cross-bars on trunk and widening significantly on caudal peduncle (vs gradually widened, Fig. 3E, F); (8) lower jaw with one row of large tubercles usually united basally to form a plate in male (vs 1 row of moderate tubercles well separated). The new species can be clearly distinguished from O. bidens by the following features: (1) absence of distinct anterior notch on upper lip (vs presence of conspicuous anterior notch on upper lip); (2) two rows of pharyngeal teeth (vs 3 rows); (3) maxillary extending to or slightly beyond the vertical of anterior margin of ...

Etymology: Iridescens is the Latin form of the word iridescent. Here, it refers to the unique body color, which is brighter than that of any known species in the genus. In this study, we propose the Chinese common name Hóng Cǎi Mǎ Kǒu Yú (虹彩马口鱼).

 

Image of the habitat of Opsariichthys iridescens sp. nov., near riverbed with stones.

 

 Xin Peng, Jia-Jun Zhou, Hong-Di Gao and Jin-Quan Yang. 2024. A New Species of Opsariichthys (Teleostei, Cypriniformes, Xenocyprididae) from Southeast China. ZooKeys. 1214: 15-34. DOI: doi.org/10.3897/zookeys.1214.127532

[Ichthyology • 2024] Opsariichthys rubriventris • A New Species of Cyprinid Genus Opsariichthys (Teleostei: Cyprinidae) from the Pearl River, Southern China

Opsariichthys rubriventris  J.-B. Chen, Y.-T. Li, J.-J. Zhou & J.-J. Wang,

in Chen, Y.-T. Li,Zhou, C. Li, Weng, Lin et Wang, 2024. 

广东马口鱼  ||  DOI: 10.3390/d16100596

Abstract

A new cyprinid fish, Opsariichthys rubriventris sp. nov., is described from the Xizhijiang River, a tributary of the Pearl River basin in Huizhou City, Guangdong Province, southern China. The species is distinguished from all other congeners by the following combination of characters: predorsal scales 13–14; lower jaw projecting slightly beyond upper jaw; cheek with two mainly longitudinal rows of tubercles; and lower jaw, belly, pectoral fin, and anterior margin of anal fin in adult males being reddish-orange. The principal component analysis result of the morphological data indicated that O. rubriventris sp. nov. could be clearly distinguished fromfour other congeners. The phylogenetic analysis conducted in this study, utilizing both Maximum Likelihood (ML) and Bayesian Inference (BI) methods, supported the monophyly of the novel species O. rubriventris sp. nov. at the species level. Additionally, the genetic distance analysis revealed that O. rubriventris sp. nov. exhibits a genetic distance ranging from 0.14 to 0.16 with its congeneric species, further affirming its taxonomic status.

Keywords: taxonomy; phylogenetic analysis; Guangdong province; opsariichthine

Opsariichthys rubriventris sp. nov.:
 (a) freshly preserved male;
(b) male, preserved specimen, SCNU202404001, holotype, 67.9 mm SL, Huidong County, Huizhou City, Guangdong Province, China;
(c) female, SCNU202404002, paratype, 60.7 mm SL, Huidong County, Huizhou City, Guangdong Province, China.

Opsariichthys rubriventris sp. nov. J.-B. Chen, Y.-T. Li, J.-J. Zhou & J.-J. Wang, 

 Diagnosis: 

Opsariichthys rubriventris sp. nov. can be distinguished from the congeneric species by the following combination of morphological characters: (1) no maxillary barbels; (2) no anterior notch at the tip of the upper lip; (3) lateral line scales 39–43; (4) predorsal scales 13–14; (5) narrow body width; (6) lower jaw protrudes slightly beyond the front of the snout; (7) 2 rows of pearl organs of the cheek, and the pearl organs are cone-shaped; (8) the pectoral fins of adult males do not extend to the origin of the pelvic fins; (9) adult males have significant nuptial coloration; the lower jaw and ventral side are orange-red; (10) the envelope of the first six rays of the anal fin of adult males, females, and juveniles is orange-red, and the remaining rays gradually become colorless.

Morphologically, O. rubriventris sp. nov. can be clearly distinguished from its congeners O. bidens and O. hainanesis based on these characteristics: O. bidens and O. hainanesis have a concave notch at the front of the upper jaw in which the anterior end of the mandible fits, while the O. rubriventris sp. nov. does not have a deep notch at the front of the upper jaw ...

Etymology: The specific epithet rubriventris is constructed from the Latin words ruber, meaning red, and venter, meaning belly, an adjective, referring to the red belly of the mature males. In addition, since O. rubriventris sp. nov. is only distributed in Guangdong Province, China, we suggest its Chinese vernacular to be “广东马口鱼”.

  Jia-Bo Chen, Ying-Tao Li, Jia-Jun Zhou, Cheng Li, Guo-Xi Weng, Hung-Du Lin and Jun-Jie Wang. 2024. A New Species of Cyprinid Genus Opsariichthys (Teleostei: Cyprinidae) from the Pearl River, Southern China. Diversity. 16(10), 596. DOI: doi.org/10.3390/d16100596

[Ichthyology • 2021] Island Colonization by A ‘Rheophilic’ Fish: the Phylogeography of Garra ceylonensis (Teleostei: Cyprinidae) in Sri Lanka

 Garra ceylonensis   

in Sudasinghe, Dahanukar, Raghavan, ... et Meegaskumbura, 2021.

 DOI: 10.1093/biolinnean/blaa221

 twitter.com/HiranyaSud

 

Abstract

Despite exhibiting multiple morphological adaptations to living in swiftly flowing water (rheophily), Garra ceylonensis is one of the most widely distributed freshwater fish in Sri Lanka. It is thus an ideal organism to reconstruct the evolutionary history of a widespread, yet morphologically specialized, freshwater fish in a tropical-island setting. We analysed the phylogenetic and phylogeographic relationships of G. ceylonensis based on two mitochondrial and one nuclear genes. G. ceylonensis is shown to be monophyletic, with a sister-group relationship to the Indian species Garra mullya. Our results suggest a single colonization of Sri Lanka by ancestral Garra, in the late Pliocene. This suggests that the Palk Isthmus, which was exposed for most of the Pleistocene, had a hydroclimate unsuited to the dispersal of fishes such as Garra. G. ceylonensis exhibits strong phylogeographic structure: six subclades are distributed as genetically distinct populations in clusters of contiguous river basins, albeit with two exceptions. Our data reveal one or more Pleistocene extirpation events, evidently driven by aridification, with relict populations subsequently re-colonizing the island. The phylogeographic structure of G. ceylonensis suggests inter-basin dispersal largely through headwater capture, likely facilitated by free-swimming post-larvae. The Peninsular-Indian species G. mullya comprises two genetically distinct parapatric clades, which may represent distinct species.

Keywords: biogeography, dispersal, freshwater fish, Labeoninae, phylogeny, Pleistocene, torrent fish

Garra ceylonensis Bleeker, 1863

Hiranya Sudasinghe, Neelesh Dahanukar, Rajeev Raghavan, Tharani Senavirathna, Dipeshwari J Shewale, Mandar S Paingankar, Anjalie Amarasinghe, Rohan Pethiyagoda, Lukas Rüber and Madhava Meegaskumbura. 2021. Island Colonization by A ‘Rheophilic’ Fish: the Phylogeography of Garra ceylonensis (Teleostei: Cyprinidae) in Sri Lanka. Biological Journal of the Linnean Society. blaa221. DOI: 10.1093/biolinnean/blaa221

 twitter.com/HiranyaSud/status/1359782960258514944

     

     

[Ichthyology • 2020] Rasbora marinae • A New Species of Cyprinid Fish (Cypriniformes: Danionidae) from northwestern Borneo

 Rasbora marinae 

Tan & Kottelat, 2020

  RAFFLES BULLETIN OF ZOOLOGY. 68

Abstract

 Rasbora marinae, new species, is described from Brunei Darussalam and northern Sarawak, Borneo. It shares with R. cephalotaenia the colour pattern of a mid-lateral stripe from tip of snout to end of median caudal-fin rays and rows of black spots on the flank, including two rows along edges of the mid-lateral stripe; it differs from R. cephalotaenia in retaining the mid-lateral stripe in adults, and in the absence of a conspicuous black blotch at the middle of the caudal-fin base. 

Key words. Southeast Asia, biodiversity, taxonomy, Cypriniformes, peat swamps

Fig. 1. Rasbora marinae, ca. 60 mm SL; Sarawak: Tatau; freshly caught specimen; not preserved.

Fig. 2. Rasbora marinae, Brunei.
A, ZRC 51189, holotype, 97.1 mm SL;
B, ZRC 51190, paratype, 36.5 mm SL.

Fig. 3. Rasbora cephalotaenia, colouration of freshly caught specimens.
A, Kahayan basin, clear water stream, ca. 50 mm SL;
B, Sebangau basin, black water stream, ca. 60 mm SL.

Fig. 6. Distribution of Rasbora cephalotaenia (squares) and Rasbora marinae (circles) in Borneo and Belitung Island. Hollow symbols represent type localities.

Rasbora marinae, new species

Diagnosis. Rasbora marinae is differentiated from congeners by the following combination of characters: a mid-lateral black or dark brown stripe from the tip of the snout to the end of the median caudal-fin rays; rows of black spots on the flank, including two rows along the edges of the midlateral stripe; lateral line complete, with 30–31 + 1–2 scales; 12 circumpeduncular scale rows. Rasbora marinae is very similar to R. cephalotaenia from which it differs in retaining the mid-lateral stripe in adults (vs. stripe disappearing with increasing size, leaving only the 2 rows of black spots along its edges), and the absence of a conspicuous black blotch at the middle of the caudal-fin base (vs. presence).

Distribution. Rasbora marinae is currently found in Belait and Tutong Districts, Brunei Darussalam; and in Sarawak, north of Tatau basin including Lambir Hills, to Baram basin (see map in Fig. 6; Zakaria-Ismail, 1984; Parenti & Meisner, 1995; Sulaiman & Shahdan, 2003; Tan & Lim, 2007; unpublished data).

Etymology. This species is named for Marina Wong (Brunei Museum, retired) in appreciation of her contributions to the knowledge of the natural history of Southeast Asia and her generous help in organising fieldwork in Brunei for the first author and team.

Tan Heok Hui and Maurice Kottelat. 2020. Rasbora marinae, A New Species of Cyprinid Fish from northwestern Borneo (Teleostei: Danionidae). RAFFLES BULLETIN OF ZOOLOGY. 68: 750–758. DOI: 10.26107/RBZ-2020-0086

 

[Ichthyology • 2020] Diversity, Phylogeny and Biogeography of Systomus (Teleostei, Cyprinidae) in Sri Lanka

in Sudasinghe, Pethiyagoda, Raghavan, et al., 2020.

 DOI: 10.1111/zsc.12445  

 facebook.com/HiranyaSudasinghe

Abstract

The South and South‐East Asian freshwater fish genus Systomus (Cyprinidae) comprises 17 valid species. Six nominal species, including three endemics, have been reported from Sri Lanka, a continental island separated from India by a shallow‐shelf sea. The species diversity of Systomus on the island has until now not been assessed; neither has an evaluation been made of their phylogenetic history. Here, based on an analysis of the nuclear recombination activating protein 1 (rag1), and mitochondrial cytochrome c oxidase subunit 1 (cox1) and cytochrome b (cytb) gene markers, and a morphological examination of 143 specimens from 49 locations in Sri Lanka, we reassess the diversity of Systomus on the island and analyse patterns of their evolution and biogeography. Divergence‐time estimates, based on a substitution rate calibration, date the basal split between Systomus and its sister group, the Afrotropical small barbs, to 30.0 Ma (95% highest posterior density: 25.4–35.2 Ma). The species of Systomus belong to two distinct clades. The first includes the Sri Lankan endemics S. asoka, S. martenstyni and S. pleurotaenia, which comprise an insular diversification following the immigration of a common ancestor during the Oligocene. The second, which includes the remaining species of Indian, Sri Lankan and South‐East Asian Systomus, has a crown age dating to the Late Miocene. Morphological and molecular species delimitation analyses failed to validate the two nominal species, S. spilurus and S. timbiri, previously reported from Sri Lanka: both are considered synonyms of S. sarana, as are the nomina S. chryseus, S. chrysopoma, S. laticeps, S. rufus, S. pinnauratus and S. subnasutus. Four genetically and geographically discrete lineages of S. sarana occur in the island, and three in India. Molecular species delimitation analysis suggests these all belong to a single species, S. sarana. The genetically distinct Sri Lankan populations of S. sarana result from Plio‐Pleistocene dispersal or vicariance events between India and Sri Lanka—as a result of emergence and inundation of the now submerged isthmus connecting the two landmasses—as well as autochthonous insular diversification.

Keywords: diversification, molecular dating, molecular systematics, phylogeography, Smiliogastrinae, taxonomy

 

Hiranya Sudasinghe, Rohan Pethiyagoda, Rajeev Raghavan, Neelesh Dahanukar, Lukas Rüber and Madhava Meegaskumbura. 2020. Diversity, Phylogeny and Biogeography of Systomus (Teleostei, Cyprinidae) in Sri Lanka. Zoologica Scripta. DOI: 10.1111/zsc.12445 

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[Ichthyology • 2020] Revision of the Genus Henicorhynchus (Cyprinidae: Labeoninae), with A Revised Diagnosis of Gymnostomus

Henicorhynchus siamensis (Sauvage, 1881)

in Ciccotto & Page, 2020. 

ปลาสร้อยขาว || DOI: 10.1643/CI-19-304  

 twitter.com/IchsAndHerps

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).

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 

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[Ichthyology • 2020] Rasbora adisi • A Molecular Phylogeny of the Freshwater‐fish Genus Rasbora (Teleostei: Cyprinidae) in Sri Lanka reveals A Remarkable Diversification—And A Cryptic Species

Rasbora adisi 

Sudasinghe, Pethiyagoda, Hettiarachchige, Ranasinghe, Raghavan, Dahanukar & Meegaskumbura, 2020

 DOI: 10.1111/jzs.12395 
 facebook.com/HiranyaSudasinghe 
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Abstract

The diversity of the freshwater‐fish genus Rasbora (Cyprinidae) on Sri Lanka (five species) is high compared with the four species reported from the peninsula of India, from which the island's cyprinid fauna is derived. The paucity of characters by which species of Rasbora can be phenotypically distinguished renders field identification difficult, adversely affecting the estimation of populations and distributions, with consequences for conservation and management, increasing also the risk of taxonomic inflation. From a sampling of 90 sites across Sri Lanka and based on phylogenetic and haplotype analyses of sequences of cox1 and cytb mitochondrial, and rag1 and irbp nuclear markers, we review the species diversity and phylogeography of Rasbora on the island. Molecular analyses recover, in addition to the five species previously reported, a new (cryptic) species: Rasbora adisi sp. nov. Uncorrected pairwise cox1 genetic distances between species range from 2.0 to 12.3 percent. The Sri Lankan diversification derives from a common ancestor which arrived from India during a sea‐level low‐stand in the mid‐Miocene (15.1 Ma [95% HPD: 11.5–19.8 Ma]), when the present‐day island was subaerially connected to the Indian subcontinent by a broad isthmus. This gave rise to a clade comprising five species—Rasbora adisi sp. nov., Rasbora armitagei, Rasbora microcephalus, Rasbora naggsi and Rasbora wilpita —with a crown age of 9.9 Ma (95% HPD: 7.1–13.3 Ma) and to a clade comprising Indian and Sri Lankan populations of Rasbora dandia, which themselves are reciprocally monophyletic. Morphological analysis of 334 specimens discriminates between most species which, however, are most reliably diagnosed by chromatic characters. The four endemic species exhibit a pattern of inter‐basin dispersal via headwater capture, followed by vicariance, explaining the high diversity of the genus on the island.

Keywords: cryptic species, diversification, freshwater fish, India, species delimitation

 a new (cryptic) species: Rasbora adisi sp. nov.  

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Live color pattern variation in species of Rasbora in Sri Lanka.
(a)  Rasbora adisi sp. nov., ~75 mm SL, Kotagama, Gal Oya basin; (b) Rasbora microcephalus, ~60 mm SL, Yakkala, Attanagalu Oya basin;
(c) Rasbora naggsi, ~55 mm SL, Hambegamuwa, Walawe River basin; (d) Rasbora dandia, ~65 mm SL, Pitigala, Bentara River basin;
(e) Rasbora armitagei, ~65 mm SL, Weralugahamula, Kalu River basin; (f) Rasbora wilpita, ~70 mm SL, Kottawa Forest Reserve, Gin River basin. 

 Rasbora adisi, sp. nov

Etymology: The species name adisi, a noun in apposition, means mysterious or enigmatic in Sinhala: an allusion to the cryptic nature of this species.

Hiranya Sudasinghe, Rohan Pethiyagoda, Ranasinghe Hettiarachchige,Tharindu Ranasinghe, Rajeev Raghavan, Neelesh Dahanukar and Madhava Meegaskumbura. 2020. A Molecular Phylogeny of the Freshwater‐fish Genus Rasbora (Teleostei: Cyprinidae) in Sri Lanka reveals A Remarkable Diversification—And A Cryptic Species. Journal of Zoological Systematics and Evolutionary Research. DOI: 10.1111/jzs.12395

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[Ichthyology • 2020] Rhodeus cyanorostris & R. nigrodorsalis • Two New Species of Rhodeus (Cyprinidae: Acheilognathinae) from the River Yangtze, China

Rhodeus nigrodorsalis &  

R. cyanorostris 

Li, Liao & Ara,. 2020

 DOI: 10.25225/jvb.19055

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Abstract

Rhodeus cyanorostris sp. nov. and R. nigrodorsalis sp. nov. are described from two tributaries of the River Yangtze, in Sichuan and Jiangxi Provinces, China, respectively. Both species have a small number of branched dorsal-fin rays (both with a mode of 8) and anal-fin rays (mode of 7-8 and 8, respectively), which makes them easily distinguished from all congeners. Rhodeus cyanorostris sp. nov. differs from R. nigrodorsalis sp. nov. in having more predorsal scales (14-16 vs. 12-13), fewer pectoral-fin rays (10-11 vs. 12), a shorter major axis of the eggs (2.5-2.8 mm vs. mostly 3.3-3.5 mm), absence of two rows of light spots on the dorsal-fin rays (vs. presence), and absence of a black blotch on the dorsal fin in adult males (vs. presence). The breeding season in winter of the two new species is unique among the Acheilognathinae.

KEYWORDS: bitterling, Breeding season, egg size, lateral line, taxonomy

Fig. 6. Rhodeus cyanorostris sp. nov. in breeding season, collected from its type locality.
 A) male; B) female just before spawning (with ovipositor in maximum length). Specimen not preserved.

Rhodeus cyanorostris sp. nov. 

Diagnosis: Differs from all congeners by a combination of characters, including longitudinal scale series 32-35; pored scales absent; transverse scale series 11 (10-12); branched dorsal-fin rays 8 (rarely 7); branched anal-fin rays 7-8; vertebrae 33-34 (rarely 35); light spots on dorsal-fin rays absent; in males with nuptial colouration, snout blue, and iris, belly and all fins yellow.

Distribution and ecology: Known only from the River Bai-Tiao, a tributary of the River Yangtze, in Pidu District, Chengdu City, Sichuan Province, China (Fig. 8). The type locality was a small river with mud and gravel mixed substrate. The water level varied from approximately 0.5 to 1.0 m depth.

Adult R. cyanorostris sp. nov. are small in size. The smallest female found with mature oocytes was 23.6 mm SL. The main spawning season is in winter, from January to March. Females spawn several times during the spawning period and usually releases clutches of 3-8 eggs when squeezed manually. Host mussels are not known.

Etymology: The specific name, cyanorostris, is derived from the Latin terms cyano for blue and rostris for snout, a noun, alluding to the distinctive blue snout in nuptial males.

Fig. 14. Rhodeus nigrodorsalis sp. nov. in breeding season, collected from its type locality. A) male; B) female just before spawning (with ovipositor in maximum length). Specimen not preserved.

Rhodeus nigrodorsalis sp. nov.  

Diagnosis: Differs from all congeners by a combination of characters, including longitudinal scale series 33-35; pored scales 2-4 (rarely 0); transverse scale series 10 (rarely 11); branched dorsal-fin rays 8; branched anal-fin rays 8 (rarely 9); vertebrae 34-35 (rarely 33); iris yellowish, belly yellow, dorsal-fin membrane dark black, and a vertical band on the anterior of flank in nuptial males.

Distribution and ecology: Known only from the River Le-An in Wuyuan County, Jiangxi Province (type locality) and the River Lv in Qimen County, Anhui Province both flowing into Lake Poyang in the River Yangtze basin (Fig. 8). The type locality is a large river where R. nigrodorsalis sp. nov. occurs mostly in shallow marginal areas with a substrate of mixed sand and mud.

Female R. nigrodorsalis sp. nov. starts spawning at just 30 mm SL, but with the maximum length of this species seen in a captive male kept in an aquarium for 17 months of 47.1 mm SL. The main spawning season is during winter, from January to March. Females spawn several times during the spawning period and usually release 2-7 eggs in a clutch when squeezed manually. Host mussels are not known.

Etymology: The specific name, nigrodorsalis, is derived from the Latin terms nigro for black and dorsalis for dorsal fin, a noun, alluding to the diagnostic black dorsal-fin membrane in adult males.

Fig. 15. Dorsal fin of adult males of five Rhodeus species.
A) Rhodeus nigrodorsalis sp. nov. in life, SOU 1903001, 47.1 mm SL; B) R. nigrodorsalis sp. nov. in preservative, SOU 1712002, 37.9 mm SL;
C) Rhodeus cyanorostris sp. nov. in preservative, SOU 1801001, holotype, 32.1 mm SL; D) R. amarus in life, 59.8 mm SL (specimen not preserved), collected from Ballica, Turkey;
E) R. shitaiensis in life, 56.1 mm SL (specimen not preserved), collected from Shitai County, Anhui Province, China; F) R. rheinardti in life, 49.3 mm SL (specimen not preserved), collected from Hue City, Vietnam.

Fan Li, Te-Yu Liao and Ryoichi Arai. 2020. Two New Species of Rhodeus (Teleostei: Cyprinidae: Acheilognathinae) from the River Yangtze, China. Journal of Vertebrate Biology. 69(1); 1-17. DOI: 10.25225/jvb.19055

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