Midlateral Blotches Research Articles

Bisecting the type series of Leporinus paranensis Garavello and Britski, 1987 (Characiformes, Anostomidae)

The type series of Leporinus paranensis includes two distinct species, one of which is herein described as new. Leporinus paranensis is redescribed based on its holotype, two paratypes, and additional specimens recently sampled in tributaries of the Grande river, in the north portion of the upper Paraná basin in Brazil. A new species of Leporinus is described based on specimens collected in all major tributaries of the upper Paraná basin in Brazil, and tributaries of the Paraná river in Paraguay. Both species share the presence of three unicuspid teeth on the premaxillary and four on dentary, terminal mouth and three dark midlateral blotches on the body. The new species is distinguished from L. paranensis based on the number of scale series around the caudal peduncle (12 vs. 16). The variation in the body shape of both species were compared through a Principal Component Analysis and showed that they share a similar body shape. Species delimitation analyses using DNA Barcode were applied to compare samples of the new species to congeners and corroborated the uniqueness of the new species. In addition, molecular data revealed that L. bahiensis, L. octofasciatus, and L. taeniatus are possibly closely related to the new species. The conservation status of L. paranensis and the new species are discussed using the IUCN criteria.

Oxynoemacheilus sarus/, a new nemacheilid loach from the lower Ceyhan and Seyhan in southern Anatolia (Teleostei: Nemacheilidae).

Oxynoemacheilus sarus, new species, is described from the lower Ceyhan and Seyhan drainages in southern Anatolia. It is distinguished from other Oxynoemacheilus species in Cilicia (including the Göksu, Seyhan and Ceyhan drainages) by possession of a series of irregularly shaped midlateral blotches, 3-5 dark-brown bands on the caudal fin, a complete lateral line, a forked caudal fin (shortest middle caudal-fin ray is 56-70% of longest ray of the upper caudal-fin lobe), the caudal peduncle depth 1.4-1.8 times in its length, and a suborbital groove in male individuals. The new species occurs in sympatry with superficially similar O. seyhanicola and O. evreni, and is distinguished by colour pattern as well as morphometric and molecular characters. Molecular data suggest that the closest relatives to the new species in our dataset are O. euphraticus and O. shehabi, which is characterised by a minimum K2P distance of 3.6% and 3.8%, respectively, in the COI mtDNA barcode region.

A new endangered species of Megaleporinus (Characiformes: Anostomidae) from the Rio de Contas basin, eastern Brazil.

A new species of Megaleporinus is described from the Rio de Contas, a coastal drainage of eastern Brazil, and its phylogenetic relationships are studied using molecular data. The new species is unique among Anostomidae by possessing two exclusive features: an irregular dark longitudinal stripe from supracleithrum to second midlateral blotch and anterior cranial fontanel partially closed. In addition, the new species is diagnosed by having three premaxillary teeth, three dentary teeth, 37 or 38 scales in lateral line, 16 scale rows around caudal peduncle, three dark midlateral blotches on body, and red fins in life. The new species is closely related to M. obtusidens from the São Francisco basin, corroborating previous studies that indicated that the latter represents a species complex as currently defined. The new species exhibits the first rib enlarged in mature males, a feature described for some congeners. The new species is herein considered to be Endangered under the IUCN criteria.

Taxonomic revision of the genus Anostomoides (Characiformes: Anostomidae).

A taxonomic revision of Anostomoides is herein presented based on a comprehensive revision of specimens deposited in fish collections and the literature. The present revision proposes that A. laticeps is a junior synonym of A. atrianalis, while A. passionis is a junior synonym of Leporinus nattereri, and the latter is thus transferred to Anostomoides, forming the new combination Anostomoides nattereri. Principal Components Analysis (PCA) showed that examined specimens form two distinct morphotypes, corroborating the validity of both A. atrianalis and A. nattereri. Anostomoides nattereri is distinguished from A. atrianalis by having four branchiostegal rays (vs. three), three pores in infraorbital one (vs. four), 37-39 pored lateral-line scales (vs. 41-44), lower lip with rounded dermal papillae (vs. forming ridges), three dark rounded midlateral blotches (vs. three or four vertically elongated blotches and/or a faded dark longitudinal stripe), dark lines between scale series on posterior half of body on specimens smaller than 150 mm SL (vs. dark lines absent), a greater body depth (27.6-36.2 % vs. 24.5-38.7% of SL) and smaller interorbital distance (34.4-53.8 % vs. 42.6-67.3 % of HL). Anostomoides nattereri is distributed across several tributaries of the Amazon and Orinoco rivers, whereas A. atrianalis is widespread throughout the Amazon, Orinoco, and Essequibo basins. The genus Anostomoides is currently diagnosed based on a combination of non-exclusive characters: upturned or slightly upturned mouth with four premaxillary teeth including symphyseal tooth bicuspid or with blunt cutting edge, remaining teeth slightly tricuspid (with medial cuspid distinctly larger); four dentary teeth, symphyseal tooth with truncate cutting edge (without cusps); second tooth with a single large cusp, and two lateral teeth with three or slightly more small cusps.

A new genus of Anostomidae (Ostariophysi: Characiformes): Diversity, phylogeny and biogeography based on cytogenetic, molecular and morphological data

A new genus of Anostomidae (Characiformes) is described to include ten valid extant species previously classified in Leporinus or Hypomasticus and distributed throughout most major river basins in South America: L. brinco, L. conirostris, L. elongatus, H. garmani, L. macrocephalus, L. muyscorum, L. obtusidens, L. piavussu, L. reinhardti, and L. trifasciatus. The monophyly of Megaleporinus is well-supported in a phylogenetic analysis based on two mitochondrial and three nuclear genes, as well as its sister group relationship to Abramites. Megaleporinus is diagnosed by having the exclusive combination of three unicuspid teeth on each premaxillary and dentary bone and a color pattern composed of one to four dark midlateral blotches. Additional distinguishing features and possible synapomorphies include a unique ZZ/ZW sex chromosome system confirmed for six congeners and a drumming apparatus wherein the first rib is elongated and associated with hypertrophied intercostal muscles, which was confirmed for three congeners as exclusive to mature males. Furthermore, our study identified at least four undescribed cryptic species, emphasizing the need for further taxonomic work and genetic analyses. A time-calibrated phylogenetic and biogeographical analysis of the new genus suggests that speciation in the proto-Amazon-Orinoco lineage was primarily driven by paleogeographic processes, such as the formation of the Orinoco and Tocantins basins. Dispersal and diversification of the genus in coastal basins draining the Eastern Brazilian Shield appears to have been facilitated by connections between paleo-basins during low sea level periods and headwater captures between coastal and inland watersheds. The present contribution demonstrates the importance of integrating data from morphology, DNA sequences and cytogenetics to advance the taxonomy and systematics of any complex species group.

A new species of Ptychochromis from southeastern Madagascar (Teleostei: Cichlidae).

We describe a new species in the endemic Malagasy cichlid genus Ptychochromis. Ptychochromis mainty, new species, is known from four individuals, all collected in the Fort Dauphin region of southeastern Madagascar, and shares a palatine morphology (eastern-type palatine) with other eastern congeners. Ptychochromis mainty is distinguished from all congeners by a nearly uniform dark brown to black pigmentation pattern in preservation and by the presence of a relatively continuous and expansive black longitudinal midlateral blotch in life, extending from the posterior margin of the opercle to the caudal peduncle. The new species is further distinguished from other eastern Ptychochromis species by having minimal or no overlap of the first supraneural with the dorsoposterior region of the supraoccipital crest (vs. marked overlap). We present a molecular-based phylogeny for all available Ptychochromis species, which supports the hypothesis that P. mainty is a distinct taxon. The new species is recovered as the sister taxon to P. grandidieri within a clade comprising species with an eastern-type palatine morphology. We present a geometric morphometric analysis that provides additional evidence to distinguish P. mainty from congeners.

Redescription of Leporinus jamesi (Characiformes: Anostomidae), a poorly known species of Leporinus from the lowlands of the central Amazon, Brazil

The poorly known Leporinus jamesiis redescribed. The species was originally described based on a single specimen collected in the rio Solimões at Manacapuru, in the central Amazon, Brazil. The holotype went missing before the species description was finished and published, and remained lost for more than a hundred years. Leporinus jamesi is distinguished from its congeners by having pectoral and pelvic fins dark, 42 to 45 scales on the lateral line, 16 scale series around the caudal peduncle, a body with two conspicuous dark midlateral blotches (the blotch on the caudal peduncle absent or inconspicuous), and four teeth on the premaxilla and dentary, including a bicuspid symphyseal tooth on the premaxilla. A principal component analysis on morphometric traits between combined samples of L. jamesi and L. amazonicus was performed showing significant morphometric differences between these species. In addition, inaccuracies in Borodin's descriptions of various species of the genus Leporinus are discussed.

A new species of Leporinus Agassiz, 1829 (Characiformes: Anostomidae) from the rio Tocantins, Brazil

A new species of Leporinus is described based on specimens from the lower rio Tocantins, Pará State, Brazil. The new species is diagnosed by having conspicuous dark spots on center of scales on anterolateral portion of body, 33 or 34 scales in lateral line, 16 scales rows around caudal peduncle, four scale rows between dorsal-fin origin and lateral line and four between lateral line and pelvic-fin origin, and four teeth on premaxilla and four on dentary. The new species is similar to Leporinus gomesi, L. granti, and L. nijsseni for having three prominent dark midlateral blotches, smaller blotches formed by dermal pigment, five of which form an interrupted "X" between head and first midlateral blotch, small dark spots formed by epidermal pigment, terminal mouth with four teeth on premaxilla and four on dentary, and relatively few scales on lateral line (less than 36). In addition, new data is provided for the type specimens of Leporinus granti and L. megalepis (=Hypomasticus megalepis),, and L. badueli is confirmed as a junior synonym of L. granti.

Two new species of cichlid fish genus Geophagus Heckel from the Rio Tocantins drainage (Perciformes: Cichlidae)

Geophagus sveni n. sp. and G. neambi n. sp. are described from the Rio Tocantins drainage of Brazil. Geophagus sveni and G. neambi differ from some of its congeners by the lack of head markings. G. sveni is distinguished from the species lacking head markings by the presence of five faint undivided vertical bars, proeminent mid-lateral blotch, and by the caudal fin vertically clear and black barred; G. neambi differs from the species lacking head markings by the possession of eight or nine vertical, parallel bars along the flank, the bar containing mid-lateral spot bifurcate above and below midlateral blotch and by the caudal fin bearing rounded white spots. Geophagus sveni differs from the sympatric and syntopic Geophagus neambi by the presence of five faint vertically bars (vs. eight or nine conspicuous dorso-ventral bifurcated vertically bars).

Threatened fishes of the world: Crystallaria cincotta Welsh and Wood 2008 (Percidae)

Common name: Diamond Darter. Conservation status: Listed as a “species of special concern” by West Virginia Division of Natural Resources. Extirpated from Tennessee (Etnier and Starnes 1993), Kentucky (Burr and Warren 1986), and Ohio (Trautman 1957). Systematics: Sister species of Crystallaria asprella (Wood and Raley 2000; Morrison et al. 2006). Identification: C. cincotta is overall translucent with silvery white ventral side of the body and head and four wide olive-brown saddles on the back and upper side. Preorbital blotch and 12–14 mid-lateral blotches along side (Welsh and Wood 2008). Longest known individual is 77 mm SL (Welsh and Wood 2008). D1 11–13 (12), D2 11–15 (13), A I, 11–13 (13), lateralline scales 83–93 (87), cheek scale rows 1–4 (2), opercle scale rows 1–4 (2). Pelvic fins with falcate posterior margin. Drawing by SAW, 75 mm SL male, Elk River, WV. Distribution: Extant population in the Elk River of Kanawha River drainage, WV (Cincotta and Hoeft 1987; Welsh and Wood 2008). The range previously included the Muskingum River, OH, Ohio River, OH, Green River, KY, and the Cumberland River drainage, KY and TN. Abundance: Rare, known from 12 individuals (Welsh and Wood 2008). Habitat and ecology: Collected from riffles and pools with <1.5 m depth, moderate flow, and sand, gravel, and cobble substrates (Osier 2005). Based on habitats used by its sister species (C. asprella), the Diamond Darter may also use areas of deeper pool and run habitats. Reproduction: George et al. (1996) reported on reproduction of the sister species, C. asprella; however, no information is available on reproduction of C. cincotta. Threats: Grandmaison et al. (2003) reported siltation from current landuse practices as a major concern for conservation of Crystallaria in the Elk River drainage. Conservation action: No current conservation action has been implemented. Environ Biol Fish (2009) 84:191–192 DOI 10.1007/s10641-008-9405-z

Ptychochromis inornatus: A New Cichlid (Teleostei: Cichlidae) from Northwestern Madagascar, with a Discussion of Intrageneric Variation in Ptychochromis

Abstract Ptychochromis inornatus, n. sp., is described from the Ankofia basin, northwestern Madagascar. The new species is diagnosed from congeners by the absence of large, black midlateral blotches or bars, and the presence of only two rows of teeth on the second pharyngobranchial toothplate, a robust uncinate process of the first epibranchial bone that is at least twice the diameter of the anterior arm, anterior chest scales that are reduced in size and embedded, a rounded and truncate postero-dorsal margin on the supraoccipital crest, and red fin coloration in life. Ptychochromis inornatus is endemic to the Ankofia drainage basin, with a geographic range extending from the Anjingo River northward to Lake Andrapongy and its surrounding drainages. Intrageneric variation within Ptychochromis is also discussed and comparisons made to the new species.

Description of a new Acaronia species (Teleostei, Cichlidae) from the Rio Orinoco and Rio Negro drainages

Acaronia vultuosa sp.n. occurs in the Rio Orinoco and upper Rio Negro drainages. In the Rio Negro it overlaps slightly the range of its only congener, A. nassa (Heckel), from which it can be distinguished by (1) the lack of microbranchiospines on the first gill arch, (2) thc separate instead of coalesced anterior gill rakers on the first gill arch, and (3) the colour pattern, which includes a much larger midlateral blotch and a different pattern of dark markings on the head.