Gelanoglanis, BOHLKE, 1980

GENUS GELANOGLANIS BÖHLKE, 1980 View in CoL (CLADE 32)

Gelanoglanis Böhlke, 1980: 150 View in CoL (type species: Gelanoglanis stroudi Böhlke, 1980 View in CoL ; type by original designation. Gender masculine).

Included species: Gelanoglanis nanonocticolus Soares-Porto, Walsh, Nico & Netto, 1999 View in CoL , Gelanoglanis pan Calegari, Reis & Vari, 2014 View in CoL , Gelanoglanis stroudi Böhlke, 1980 View in CoL , Gelanoglanis travieso Rengifo, Lujan, Taphorn & Petry, 2008 View in CoL , Gelanoglanis varii Calegari & Reis, 2016 , Gelanoglanis sp. 1 Peru Sabaj-Pérez et al., undescribed, and Gelanoglanis sp. 2 Peru Sabaj-Pérez et al., undescribed.

Diagnosis: Gelanoglanis is diagnosed by 37 molecular and 50 morphological synapomorphies. Exclusive: (1) soft papillae on maxillary barbel (char. 3502: 0 → 1); (2) nasal unossified (char. 3511: 0 → 1); (3) passageway of mandibular ramus outside to lower jaw (char. 3524: 0 → 1); (4) lateral line ending well before caudal-fin peduncle, approximately at end of anal fin (char. 3526: 0 → 2); (5) mesethmoid, elongate and narrow in dorsal view (char. 3532: 2 → 3); (6) anterior region of head with fleshy region anterior to mesethmoid and premaxillae (char. 3535: 0 → 1); (7) premaxillae positioned laterally to mesethmoid in dorsal view (char. 3536: 0 → 2); (8) anteroventral portion of mesethmoid with process developed into laminar keel (char. 3537: 2 → 0); (9) anterior cranial fontanel absent (char. 3539: 0 → 1); (10) vomer fused to mesethmoid (char. 3572: 0 → 1); (11) premaxilla vertically laminar (char. 3583: 0 → 3); (12) sesamoid 1 extremelly reduced, spherical to ovoid shaped (char. 3621: 1 → 3); (13) first two branchial arches without gill rakers (char. 3635: 1 → 2); (14) third and fourth branchial arches without gill rakers (char. 3636: 0 → 2); (15) third proximal radial of pectoral fin absent (char. 3698: 0 → 1); (16) dorsal process of cleithrum distinctively large, approximately the same length as the pectoral-fin spine (char. 3708: 0 → 1); (17) scapulo-coracoid without bony crest (char. 3719: 1 → 0); (18) proximal radials of anal- fin totally fused to each other in mature males (char. 3739: 0 → 1); and (19) first unbranched ray of ventral lobe of caudal fin articulated on parahypural (char. 3749: 1 → 0). Non-exclusive: (20) one pair of mental barbels (char. 3504: 1 → 0), convergent in Ageneiosini ; (21) antorbital not participating on orbital margin (char.3514: 1 → 0), convergent in Trachelyopterus insignis and Ageneiosini ; (22) ventral projection on antorbital absent (char. 3516: 1 → 0), convergent in Asterophysus ; (23) lateral ethmoid contacting only mesial portion of antorbital(char.3517:2→0),convergent in some species of Ageneiosus and Tympanopleura , Entomocorus , Liosomadoras and Pseudauchenipterus ; (24) contact between antorbital and lateral ethmoid by ligament (char. 3518: 2 → 0), convergent in Tympanopleura brevis and Ageneiosus uranophthalmus ; (25) infraorbitals not ossified (char. 3519: 3 → 6), convergent in small body-sized Tatia of clade 50 (except Tatia creutzbergi ); (26) mesethmoid elongated, with length at least twice its width (char. 3533: 1 → 0), convergent in Auchenipterini (except Pseudauchenipterus ) and Tetranematichthys ; (27) anteromedial portion of mesethmoid not contacting premaxilla (char. 3534: 0 → 1), convergent in Ageneiosini and Pseudepapterus ; (28) posterior process of epioccipital forming simple spine (char. 3563: 3 → 0), convergent in Asterophysus , Auchenipterichthys , Balroglanis macracanthus , Balroglanis schultzi , Entomocorus and Trachelyopterichthys ; (29)premaxilla straight (char.3584: 0 → 1), convergent in Auchenipterichthys , Entomocorus , Glanidium catharinensis and Glanidium cesarpintoi ; (30) distal portion of premaxilla extended (char. 3586: 0 → 1); convergent in Ageneiosini , Auchenipterus and Pseudepapterus cucuhyensis ; (31) premaxillary teeth straight (char. 3589: 0 → 1), convergent in several auchenipterids; (32) coronomeckelian bone positioned oblique (char. 3596: 0 → 1), convergent in most species of Tatia , Duringlanis romani , Balroglanis macracanthus and Liosomadoras ; (33) coronoid process on mandible smaller than posterior portion of dentary (char. 3601: 0 → 2), convergent in some species of Ageneiosus and Tympanopleura , Entomocorus and Epapterus ; (34) hyomandibula articulated only to sphenotic (char. 3619: 1 → 3), convergent in several auchenipterids; (35) hyomandibula separated from metapterygoid (char.3620: 0 → 1), convergent in Ageneiosini , Centromochlus , Tatia , Tetranematichthys , Pseudobunocephalus and several doradids; (36) interopercle large, plate shaped (char. 3626: 2 → 0), convergent in Auchenipterichthys and Trachelyopterichthys ; (37) third and fourth branchial arches without gill rakers (char. 3642: 0 → 2), convergent in Ageneiosus and Tympanopleura ; (38) first hypobranchial elongate, cylindrical (char. 3645: 1 → 3), convergent in Asterophysus ; (39) posterior process of third epibranchial approximately of same length as its mesial portion (char. 3648: 0 → 1), convergent in several auchenipterids; (40) distal portion of posterior process of third epibranchial pointed (char. 3649: 0 → 1), convergent in several auchenipterids; (41) Müllerian ramus reduced, not surpassing one-half the length of the transcapular process (char. 3661: 0 → 1), convergent in Ageneiosus and Pseudepapterus ; (42) proximal extremity of ribs straight (char. 3649: 1 → 0), convergent in several auchenipterids; (43) serration on lateral margin of pectoral-fin spine absent (char. 3702: 1 → 0), convergent in some species of Ageneiosus , Centromochlus and Auchenipterini (except Auchenipterus fordicei and Entomocorus ); (44) posterodorsal process of cleithrum absent (char. 3709: 0→1),convergentinsomespeciesof Tatia and Duringlanis perugiae ; (45) posterior process of cleithrum moderated in size, approximately half the length of the pectoral-fin spine (char. 3711: 2 → 1), convergent in Auchenipterini (except Pseudepapterus ), Tocantinsia , Trachelyopterus and Spinipterus sp. ‘oncinha’; (46) posterior process of cleithrum smooth, without ornamentation (char. 3712: 1 → 0), convergent in Tympanopleura brevis , Tympanopleura rondoni , Asterophysus, Auchenipterini (except Pseudauchenipterus flavescens and Pseudauchenipterus affinis ) and Tetranematichthys ; (47) contralateral anteromedial processes of basipterygium sutured to each other only on anterior portion (char. 3723: 0 → 2), convergent in Centromochlus , Entomocorus , Gephyromochlus , Tatia (except Tatia musaica and Tatia meesi ), Trachelyopterichthys and some species of Trachelyopterus ; (48) basal process of pelvic-fin rays posteromedially oriented (char. 3732: 1 → 0), convergent in several auchenipterids; (49) hypurapophysis of type D ( Lundberg & Baskin, 1969) (char. 3747: 2 → 3), convergent in some species of Trachelyopterus ; and (50) ventral process of hypurapophysis absent (char. 3748: 1 → 0), convergent in several auchenipterids.

Additional diagnosis: posterior naris long, narrow and located immediately anterior to eye ( Calegari et al., 2014: char. 2); and mouth oblique and sinuous, with free fleshy flange around angle of mouth opening ( Calegari et al., 2014: char. 5). The only synapomorphy proposed by Soares-Porto et al. (1999) not included in the present analysis is the short base in all fins (except caudal fin), including relatively few fin rays ( Calegari et al., 2014: char. 6). However, the present results indicate that Gelanoglanis is similar to the remaining Centromochlinae with respect to the number of fin rays and the size of the fin base, not representing a diagnostic feature ( Böhlke, 1980; Soares-Porto et al., 1999; Calegari et al., 2014).

Comparisons: Gelanoglanis is the only miniature group of species in the family, thus easily distinguished by the smaller body size. It differs from other auchenipterid genera by the laterally compressed head (vs. rounded head, slightly or deeply depressed), sinuous shape of the mouth in lateral view (vs. mouth straight), anterior portion of snout with a fleshy region, not supported by skeleton (vs. anterior portion of snout structured by premaxilla and mesethmoid bones), premaxillae positioned laterally to the mesethmoid (vs. premaxilla positioned anterior or anterolaterally), premaxilla laminar and oriented vertically to the head (vs. premaxilla horizontally oriented), passageway of mandibular ramus of lateral line system running outside to the lower jaw (vs. mandibular ramus running inside dentary), lateral line ending well before caudal-fin peduncle, approximately at the end of the anal fin (vs. reaching near or surpassing the caudal fin). Furthermore, it differs from all auchenipterids, except Ageneiosini , by having one pair of mental barbels (vs. two pairs of mental barbels).