Systematics of the Neotropical Catfish Genera Nemuroglanis Eigenmann and Eigenmann 1889, Imparales Schultz 1944, and Medemichthys Dahl 1961 (Siluriformes: Heptapteridae)
The phylogenetic relationships of the poorly known nominal heptapterid genera Nemuroglanis, Imparales, and Medemichthys, and the validity of their species, are examined on the basis of type- and recently discovered material. These genera are known from the Amazon River basin of Brazil, Ecuador, Peru, and Venezuela, and the Orinoco River basin of Venezuela. Two species were described in Nemuroglanis, Nemuroglanis lanceolatus, its type species, from the Amazon River, and Nemuroglanis pauciradiatus, from the Orinoco and Negro River basins. Imparales includes its type species, Imparales mariai, from the Orinoco River basin, and Imparales panamensis, from Panama. Medemichthys, also known from Orinoco River basin, is monotypic, with Medemichthys guayaberensis as its type species. Based on the study of morphological characters, we conclude that (1) N. lanceolatus, N. pauciradiatus, and I. mariai constitute a monophyletic group within the Heptapteridae, but I. panamensis is not a member of this clade and is instead part of a currently unresolved clade that includes the genera Chasmocranus, Pariolius, and Phenacorhamdia; (2) N. lanceolatus, N. pauciradiatus, and I. mariai are valid species, but M. guayberensis is a junior synonym of I. mariai; (3) N. lanceolatus and N. pauciradiatus are sister species, and I. mariai is sister to that clade; and (4) the distinctions between I. mariai and the two species of Nemuroglanis render the recognition of both Nemuroglanis and Imparales problematic, prompting us to include I. mariai in an expanded Nemuroglanis.Abstract
Species of Nemuroglanis. (A) Nemuroglanis lanceolatus, MZUSP 23448, 34.7 mm SL; (B) Nemuroglanis pauciradiatus, INPA 20524, 30.6 mm SL; (C) Nemuroglanis mariai comb. nov., USNM 121251, 37.8 mm SL, holotype of Imparales mariai; (D) N. mariai comb. nov., SU 53804, 33.9 mm SL
Cranium of Nemuroglanis lanceolatus, in dorsal view, MZUSP 23412, 34.6 mm SL. Abbreviations: AF, anterior fontanel; AN, antorbital; AP, autopalatine; AT, antorbital tubule; EC, ethmoid cartilage; EP, epioccipital; ES, extrascapular; EX, exoccipital; FR, frontal; i3, infraorbital sensory branch 3; LE, lateral ethmoid; ME, mesethmoid; MX, maxilla; NA, nasal; PF, posterior fontanel; PM, premaxilla; PT, pterotic; s1, supraorbital sensory branch 1; SO, supraoccipital; SP, sphenotic; ST1–2, suborbital tubules 1 and 2; and ST4, suborbital tubule 4. Scale bar = 1 mm
Pectoral girdle and fins of Nemuroglanis pauciradiatus, in dorsal view, MZUSP 45908, 28.4 mm SL. Abbreviations: AP, articular cleithral process; CB, posterior complex bone of pectoral girdle; CL, cleithrum; MA, mesocoracoid arch; and PP, posterior cleithral process. Scale bar = 2 mm
Caudal skeleton and associated rays of Nemuroglanis pauciradiatus, in lateral view, MZUSP 45908, 28.4 mm SL. Abbreviations: CF, caudal artery foramen; EP, epural; HA + HAS, hypurapophysis and hypurapophysis secondary; HU1 + HU2, complex plate formed by hypurals 1 and 2; HU3 + HU4 + HU5, complex plate formed by hypurals 3, 4, and 5; PH, parhypural; PU1 + U1, complex centrum formed by preural centrum 1 and ural centrum 1; PU2, preural centrum 2; and UR, uroneural. Scale bar = 1.5 mm
Dorsal view of head of: (A) Nemuroglanis lanceolatus, MZUSP 23470, 23.7 mm SL; (B) Nemuroglanis pauciradiatus, INPA 20524, 25.2 mm SL. Abbreviations: i1, infraorbital sensory branch 1; i3–6, infraorbital sensory branches 3–6; pm11, preoperculomandibular sensory branch 11; po1, postotic sensory branch 1; po1 + pm11, postotic-preoperculomandibular complex sensory branch (postotic sensory branch 1 + preoperculomandibular sensory branch 11); s2 + i2, supraorbital-infraorbital complex sensory branch [supraorbital sensory branch 2 + infraorbital sensory branch 2 (antorbital)]; s6, supraorbital sensory branch 6 (epiphyseal branch); s6 + s6, supraorbital complex sensory branch 6. Scale bars = 2 mm
Posterior region of pectoral girdle of (A) Nemuroglanis mariai, SU 53804, 26.7 mm SL, left lateral view; (B) Nemuroglanis pauciradiatus, MZUSP 45908, 28.4 mm SL, left lateral view. Abbreviations: CL, cleithrum; ll1-2, lateral line branches 1 and 2; LO1, first lateral line ossicle; PP, posterior cleithral process; and SC, supracleithrum. Arrow points to the dorsal concavity. Scale bars = 1 mm
Hydrographic map of South America showing geographic distribution of the genus Nemuroglanis. Symbols represent the following: circle, Nemuroglanis lanceolatus; square, Nemuroglanis mariai; and asterisk, Nemuroglanis pauciradiatus. Circled symbols represent type localities. Individual symbols may represent more than one collection. Numbers represent the following: 1, Guaviare River; 2, Meta River; 3, Napo River; 4, Ucayali River; 5, Solimões River; and 6, Negro River
Contributor Notes
(FAB) Laboratório de Ictiologia de Ribeirão Preto, Departamento de Biologia, FFCLRP, Universidade de São Paulo, Av. dos Bandeirantes 3900, 14040-901 Ribeirão Preto, São Paulo, Brazil; and (CJF) 2944 NE Couch Street, Portland, Oregon 97232. E-mail: (FAB) fabockmann@ffclrp.usp.br; and (CJF) cferraris@msn.com Send reprints requests to FAB.