Tetranematichthys, BLEEKER, 1858

Calegari, Bárbara B., Vari, Richard P. & Reis, Roberto E., 2019, Phylogenetic systematics of the driftwood catfishes (Siluriformes: Auchenipteridae): a combined morphological and molecular analysis, Zoological Journal of the Linnean Society 187, pp. 661-773 : 757-758

GENUS TETRANEMATICHTHYS BLEEKER, 1858

Tetranematichthys Bleeker, 1858b: 357 , 359 (type species: Ageneiosus quadrifilis Kner, 1857 ; type by monotypy. Gender masculine).

Included species: * Tetranematichthys barthemi Peixoto & Wosiacki, 2010 , * Tetranematichthys quadrifilis ( Kner, 1857) and Tetranematichthys wallacei Vari & Ferraris, 2006 .

Diagnosis: Tetranematichthys is diagnosed by 114 molecular and 14 morphological autapomorphies. Exclusive: (1) laterodorsal projections present on posterior portion of urohyal (char. 3631: 0 → 1); and (2) ornamentation on mental barbel present (char. 3507: 0 → 1); because this character was codified as inapplicable for Ageneiosus and Tympanopleura , which completely lack mental barbels, it was optimized as ambiguous for these genera and not listed as autapomorphic for Tetranematichthys . Non-exclusive: (3) mesethmoid elongated, approximately two times its width, or longer (char. 3533: 1 → 0), convergent in Auchenipterus , Epapterus , Entomocorus , Gelanoglanis and Pseudepapterus ; (4) epioccipital partially exposed, only anterior portion participating of cephalic shield (char. 3555: 1 → 0), convergent in Epapterus and Auchenipterus ; (5) posterodorsal process of hyomandibula small, weakly developed (char. 3613: 0 → 1), convergent in several auchenipterids; (6) levator operculi crest on hyomandibula absent (char. 3617: 1 → 0), convergent in several auchenipterids; (7) posterior projection of urohyal laminar in ventral view (char. 3629: 0 → 1), convergent in Tympanopleura brevis , Tympanopleura cryptica , Epapterus and Pseudepapterus cucuhyensis ; (8) spines present on gill rakers (char. 3640: 0 → 1), convergent in Tympanopleura atronasus , Tympanopleura brevis , Ageneiosus ucayalensis and Ageneiosus intrusus ; (9) accessory cartilage present on third and fourth basibranchials (char. 3644: 0 → 1), convergent in Ageneiosus dentatus , Ageneiosus intrusus , Ageneiosus vittatus , Ageneiosus uranophthalmus , Auchenipterus fordicei , Auchenipterichthys , Centromochlus perugiae , Pseudauchenipterus flavescens , Pseudepapterus hasemani , Trachelyichthys and Trachelyopterichthys taeniatus ; (10) ventral bony projection in last pterygiophore of dorsal fin (char. 3679: 1 → 0), convergent in Pseudauchenipterus and Pseudepapterus cucuhyensis ; (11) cartilage of lateral process of basipterygium short (char. 3727: 1 → 0), convergent in Epapterus , Glanidium , Trachelyopterichthys and Trachelyichthys sp. 1 ; (12) caudal fin truncated (char. 3746: 0 → 1), convergent in Ageneiosus inermis , Ageneiosus vittatus , Auchenipterichthys , Epapterus , Liosomadoras and Trachelyopterini (except Tocantinsia ); (13) hypurapophysis of type B ( Lundberg & Baskin, 1969) (char. 3747: 2 → 1), convergent in several auchenipterids; (14) first ventral unbranched caudal-fin ray articulated on antepenultimate haemal spine (char. 3749: 1 → 3), convergent in Trachelyopterus striatulus , Trachelyopterus porosus and Trachelyopterus aff. T. porosus ; and (15) caudal skeleton posteroventrally oriented (char. 3753: 0 → 1), convergent in Trachelyichthys , Trachelyopterichthys and Trachycorystes trachycorystes .

Comparisons: Tetranematichthys is a robust, medium body-sized genus known for nuptial males developing conspicuous sexually dimorphic features related to the dorsal-fin spine and maxillary barbel. This genus is distinguished from all auchenipterids by the digitiform ornamentation on the mental barbel (vs. mental barbel smooth, not bearing any ornamentation). It further differs from auchenipterids, except Tympanopleura and Ageneiosus , by having the predorsal region deeply arched, forming a sloped nuchal shield (vs. approximately straight in relationship to the dorsal fin region, or slightly arched, but never forming a deep slope) and by the short maxillary barbel, not surpassing the anterior margin of the orbit (vs. long maxillary barbel, extending beyond the anterior margin of the orbit). It is distinguished from all Auchenipterids, except Gelanoglanis , by the presence of one pair of mental barbels (vs. mental barbel absent in Tympanopleura and Ageneiosus , or two pairs present in remaining genera). It is distinguished from other auchenipterines, except Pseudepapterus , by the absence of an anterior nuchal plate (vs. anterior nuchal plate present); and, except for Trachelyichthys , Trachelyopterichthys and Trachycorystes trachycorystes , by having the caudal skeleton posteroventrally oriented, usually forming a subtle sloping in dorsal profile of the caudal-fin origin (vs. caudal skeleton posteriorly oriented).

GENUS TYMPANOPLEURA EIGENMANN, 1912 (CLADE 109)

Tympanopleura Eigenmann, 1912: 203 (type species: Tympanopleura piperata Eigenmann, 1912 ; type by original designation. Gender feminine).

Included species: Tympanopleura atronasus ( Eigenmann & Eigenmann, 1888) , Tympanopleura brevis ( Steindachner, 1881) , Tympanopleura cryptica Walsh, Ribeiro & Py-Daniel 2015 , Tympanopleura longipinna Walsh, Ribeiro & Py-Daniel 2015 , Tympanopleura piperata Eigenmann, 1912 , Tympanopleura rondoni (Miranda Ribeiro, 1914) and Tympanopleura sp. 1 Ribeiro et al., undescribed.

Diagnosis: Tympanopleura is diagnosed by six molecular and three morphological synapomorphies. Non-exclusive: (1) eye very large, occupying almost entire head depth (char. 3491: 0 → 1), c o n v e r g e n t i n Au ch e n i p t e r u s, P s e u d e p a p t e r u s cucuhyensis , Epapterus , Entomocorus , Centromochlus and Balroglanis (except Balroglanis carolae ); (2) upper gill rakers conical (char. 3639: 1 → 0), convergent in Auchenipterichthys, Centromochlinae (except Gelanoglanis ), Liosomadoras oncinus and Trachelyopterina ; and (3) postzygapophysis of compound centrum extended up to seventh vertebra (char. 3666: 4 → 3), convergent in Auchenipterus , Balroglanis macracanthus , Duringlanis romani , Entomocorus , Pseudauchenipterus , Trachelyichthys and Trachelyopterus teaguei .

Additional diagnosis: Tympanopleura differs from Ageneiosus by having a smaller adult body size; more gently rounded anterior profile of the head, and less protruded upper jaw, which is reflected by a shorter relative preorbital distance; large, cordiform gas bladder that is unencapsulated in bone; and prominent pseudotympanum, visible externally. Tympanopleura (except Tympanopleura piperata ) also differs from Ageneiosus by having paired posterior diverticula on the gas bladder ( Walsh et al., 2015).

Comparisons: Tympanopleura is a small body-sized Ageneiosini that is distinguished from other auchenipterines, except Ageneiosus , by having the eye ventrolaterally positioned, in such a way that it is visible in both ventral and dorsal views (vs. eye not visible in ventral view), mouth subterminal, upper jaw extended well anteriorly to the lower jaw (vs. mouth terminal, both upper and lower jaws extended anteriorly at the same vertical line) and absence of mental barbels (vs. two pairs of mental barbels present, one pair in Tetranematichthys and Gelanoglanis ). It is further distinguished from all auchenipterines, except Ageneiosus and Tetranematichthys , by the short maxillary barbel, not surpassing the anterior margin of the orbit (vs. long maxillary barbel, extending beyond the anterior margin of the orbit). It is distinguished from Ageneiosus by lacking a longitudinal sulcus on the posterior margin of the anterior cranial fontanel (except Tympanopleura rondoni ; vs. longitudinal sulcus present on posterior margin of the anterior cranial fontanel); prominent pseudotympanum, conspicuously visible externally (vs. not visible externally, or very little visible externally); except for Ageneiosus vittatus and Ageneiosus dentatus , by having the posterior margin of dorsal-fin spine serrated (vs. posterior margin of dorsal-fin spine smooth); and the Müllerian ramus large, surpassing the line through the suture in the posterolateral margin of the transcapular process (vs. reduced, not surpassing half the length of the transcapular process).