Centromochlus, KNER, 1857

GENUS CENTROMOCHLUS KNER, 1857 View in CoL (CLADE 38)

Centromochlus Kner, 1857: 430 View in CoL (type species: Centromochlus megalops Kner, 1857 View in CoL ; type by subsequent designation by Bleeker, 1862 (in Bleeker, 1862 –63): 7. Gender masculine. Species considered as junior synonym of Centromochlus heckelii View in CoL by Mees, 1974).

Included species: Centromochlus existimatus Mees, 1974 View in CoL and Centromochlus heckelii (De Filippi, 1853) View in CoL .

Diagnosis: Centromochlus is diagnosed by 20 morphological synapomorphies. Exclusive: (1) ventral keel on parasphenoid present (char. 3576: 0 → 1), exclusive within Auchenipteridae ; and (2) distal portion of Müllerian ramus protruded posteriorly (char. 3660: 0 → 1). Non-exclusive: (3) eye extremely large, occupying almost entire head depth (char. 3491: 0 → 1), convergent in Tympanopleura , Auchenipterus , Balroglanis macracanthus , Balroglanis schultzi , Entomocorus and Epapterus ; (4) contralateral mandibulae running approximately in parallel (char. 3492: 0 → 1), convergent in Balroglanis ; (5) epiphyseal bar on anterior cranial fontanel present (char. 3540: 0 → 1), convergent in Tympanopleura atronasus , Ageneiosus inermis , Auchenipterichthys longimanus , Auchenipterichthys thoracatus , Auchenipterus ambyiacus , Ferrarissoaresia , Liosomadoras , Trachelyopterichthys , Trachycorystes menezesi and some species of Trachelyopterus ; (6) coronomeckelian bone strongly sutured, continuous to anguloarticular (char. 3597: 0 → 1), convergent in Ageneiosini , Trachelyopterini (except Trachelyichthys ), Auchenipiterini (except Pseudepapterus , Pseudauchenipterus jequitinhonhae and Pseudauchenipterus nodosus ), Glanidium cesarpintoi and Gephyromochlus ; (7) ascending process of Meckel’s cartilage absent (char. 3598: 0 → 1), exclusive within Centromochlinae , convergent in Asterophysus within Auchenipteridae ; (8) coronoid process of mandible absent (char. 3600: 0 → 1), exclusive within Centromochlinae , convergent in Asterophysus within Auchenipteridae ; (9) posterodorsal portion of dentary straight (char. 3603: 0 → 1), exclusive within Centromochlinae , convergent in Asterophysus within Auchenipteridae ; (10) metapterygoid and hyomandibula separated (char. 3620: 0 → 1), convergent in Ageneiosini , Gelanoglanis and Tatia ; (11) posterior projection on urohyal in ventral view elongated, at least twice the length of the main body of the urohyal (char. 3628: 1 → 0), convergent in Ageneiosini , Auchenipterichthys longimanus , Auchenipterus , Epapterus and Pseudepapterus ; (12) distal tips of first hypobranchial approximately with same width, in hourglass shape (char. 3645: 1 → 2), convergent in Trachelyopterini , Tetranematichthys , Balroglanis , Tatia meesi and Tatia intermedia ; (13) parapophysis of fifth vertebra small, smaller than subsequent vertebra (3665: 1 → 2), convergent in Asterophysus , Auchenipterichthys , Auchenipterus osteomystax , Gelanoglanis , Glanidium catharinensis , Glanidium ribeiroi , Pseudauchenipterus , Trachelyopterichthys , Trachycorystes and some species of Tracheyopterus; (14) compound centrum including up to eighth vertebra (char. 3667: 3 → 4), exclusive within Centromochlinae , convergent in Trachelyopterini (except Trachelyichthys , Trachelyopterus albicrux and Trachelyopterus teaguei ); (15) posterior bony projection on last dorsal-fin pterygiophore present (char. 3680: 0 → 1), convergent in Ageneiosini , Auchenipterichthys (except Auchenipterichthys punctatus ), Auchenipterini , some species of Tatia , Tocantinsia and Trachelyopterina (except Spinipterus acsi ); (16) dorsal-fin spine elongated, greater than one-third of SL (char. 3685: 0 → 2), convergent in Tatia intermedia ; (17) anterior margin of pectoral-fin spine smooth, without serration (char. 3702: 1 → 0), some species of Ageneiosus, Auchenipterini (except Entomocorus and Auchenipterus fordicei ), Gelanoglanis and Gephyromochlus ; (18) pectoral-fin spine elongated, greater than one-third of SL (char. 3706: 0 → 1), convergent in Balroglanis macracanthus ; (19) posterior portion of basipterygium long, with process developed as wing (char. 3729: 0 → 1), convergent in Ageneiosini , Auchenipterina, Trachycorystina and Asterophysus ; and (20) anterior portion of fifth hypural contacting point of convergence between third and fourth hypurals and epineural (char. 3752: 0 → 1), convergent in Auchenipterinae (except Liosomadoras morrowi and Entomocorus ), Gelanoglanini and some species of Tatia .

Comparisons: Centromochlus differs from all Centromochlinae by having a ventral keel on the anterior half of the parasphenoid (vs. ventral keel absent); except for Balroglanis by having the proximal portion of the maxillary barbel ventrally positioned, in such a way that it is visible ventrally (vs. proximal portion of maxillary barbel laterally positioned, not visible ventrally); and lateral margins of the mandibulae running approximately in parallel (vs. lateral margins of mandibulae diverging laterally). Centromochlus differs from all centromochlines, except Gelanoglanis and Gephyromochlus , by having the anterior margin of the pectoral-fin spine smooth, without serration (vs. anterior margin of pectoral-fin spine serrated); from all centromochlines, except Balroglanis and Duringlanis , by having the eye ventrally displaced, in such a way that that almost the entire eye is visible in ventral view (vs. eye not visible, or little visible in ventral view) and, except Balroglanis , by having the origin of the outer mental barbel aligned near to the vertical line of the inner one ( Fig. 1A) (vs. origin of outer mental barbel positioned further laterally relative to the inner, spaced from each other by more than the barbel-base size; Fig. 1D); from Ferrarissoaresia , Duringlanis , Balroglanis and Gephyromochlus by having the posterior process of the urohyal dorsally curved, concave (vs. straight), and by the longer pectoral-fin spine, greater than one-third of SL (vs. less than one-third of SL). It differs from Balroglanis by having subequal outer and inner barbels ( Fig. 1A) (vs. outer mental barbel distinctly longest than inner; Fig. 1C). It differs from Glanidium and Tatia (except Tatia boemia and Tatia jacaratia ) by the posterior process of the cleithrum being positioned posteriorly (vs. posterior process of cleithrum dorsally inclined).

Remarks: Centromochlus was described by Kner (1857) to include two species: Centromochlus megalops , whose holotype was not designated, and Centromochlus aulopygius (currently Tatia ). In his description of Centromochlus, Kner did not designate a type species for the genus. Additionally, Kner (1857) reported the type locality for Centromochlus heckelii as Bogotá, without any additional information about a particular river or basin. Given that Bogotá is a town high in the Andes, as already noted by Mees (1974), and there is no records of this species in that region, it indicates that the type locality is not precise and likely to be wrong. Thereafter, Bleeker (1862 –63; volume II: 7), by describing a new ‘Phalanx’ Centromochli, proposed by subsequent designation Centromochlus megalops as the type species of Centromochlus , but without any further discussion about the decision. Notwithstanding, in the study addressing the Auchenipteridae and Pimelodidae diversity of fishes from Suriname, Mees (1974) proposed Centromochlus megalops Kner, 1857 as a junior synonym of Centromochlus heckelii . Controversially, Royero (1999: 257), in his PhD dissertation, analysed populations of Centromochlus heckelii from the Orinoco basin and opted for the revalidation of Centromochlus megalops . His decision was mostly based on a lot (ICN-MHN 1927) of Centromochlus from the Meta River in Colombia, which he considered to be a representative of Centromochlus megalops under a unique distinction of the absence of pigmentation on the caudal peduncle base (vs. pigmentation present in Centromochlus heckelii ). The syntypes of Centromochlus megalops analysed herein (see Supporting Information, Appendix S1, Material examined), indeed have the caudal peduncle base with such pigmentation (see Fig. 15, syntype photographs), thus not matching the unique diagnostic feature proposed to distinguish Centromochlus megalops from Centromochlus heckelii . Perhaps, this condition of a hyaline caudal-fin base is present only in populations from the Orinoco River other than that in the Meta River, and possibly represent a third species (specimens of that population were not analysed in detail in the present study). Yet, reinforcing that the population in the Meta River is Centromochlus heckelii , the anterior cranial fontanel does not reach the parieto-supraoccipital, a feature observed in specimens analysed from this locality (ANSP 131675). Consequently, the analysis of photographs and X-rays of the syntypes of Centromochlus megalops (NMW 47359, one specimen; NMW 47360; one specimen), allowed us to identify these specimens clearly and maintain this species herein as a junior synonym of Centromochlus heckelii , based on the anterior fontanel not reaching to the parieto-supraoccipital ( Fig. 15) and fewer pectoral-fin rays.

GENUS DURINGLANIS GRANT, 2015 (CLADE 39) STAT. NOV.

Centromochlus (Duringlanis) Grant, 2015: 1 (type species: Centromochlus perugiae Steindachner, 1882 View in CoL ; type by original designation. Gender masculine).

lsid: zoobank.org:act: C0379B54-EE63-48BF-AA81- A13862C6AE20

Included species: * Duringlanis altae (Fowler, 1945) , Duringlanis perugiae ( Steindachner, 1882) and Duringlanis romani ( Mees, 1988) .

Diagnosis: Duringlanis is diagnosed by eight molecular and three morphological synapomorphies. Non-exclusive: (1) terminus of lateral line approaching end of caudal-fin peduncle (char. 3526: 0 → 1), convergent in the small body-sized Tatia of clades 50 and 58; (2) one row of gill rakers on third and fourth branchial arches (char. 3636: 0 → 1), convergent in Balroglanis (except Balroglanis carolae ), Tatia simplex and Tatia aff. Tatia simplex ; and (3) serration on anterior margin of dorsal-fin spine, spine shaped (char. 3692: 0 → 1); convergent in Asterophysus , Liosomadoras and some species of Tatia ( Tatia reticulata , Tatia boemia , Tatia brunnea , Tatia caxiuanensis , Tatia nigra , Tatia strigata , Tatia sp. 2 , Tatia sp. 3 and Tatia sp. 4 ).

C o m p a r i s o n s: D u r i n g l a n i s d i f f e r s f r o m Gephyromochlus , Balroglanis and Centromochlus by having a small, rounded anterior fontanel, not surpassing the line of the posterior naris (vs. ellipsoid anterior fontanel, elongated, surpassing the line of the posterior naris); from Balroglanis by having the posterior nuchal plate rounded and lacking lateroposterior projection ( Fig. 16A) (vs. posterior nuchal plate forming an arch owing to the presence of lateral and posterior projections; Fig. 16B); spiny posterior process of epioccipital not exposed, covered by the median nuchal plate ( Fig. 16A) (vs. posterior process of epioccipital exposed beyond the lateral border of median nuchal plate; Fig. 16B); lateral border of median nuchal plate straight ( Fig. 16A) (vs. lateral border of median nuchal plate arched, curved mesially; Fig. 16B); from Centromochlus by having a shorter pectoral-fin spine, less than one-third of SL (vs. long pectoral-fin spine, greater than one-third of SL); and from Ferrarissoaresia by having the dorsal-fin spine serrated, serration particularly tiny and restricted to the tip of the spine in Duringlanis romani (vs. smooth anterior margin of dorsal-fin spine), and shorter outer mental barbel, distant from pectoral-fin origin (vs. outer mental barbel long, surpassing the pectoral-fin origin). It differs from Tatia , Gephyromochlus and Glanidium by having subequal outer and inner mental barbels ( Fig. 1B) (vs. outer mental barbel distinctly longest than inner; Fig. 1C, D); from Tatia , Centromochlus and Gelanoglanis by having the hyomandibula and metapterygoid in contact with each other (vs. hyomandibula and metapterygoid separate from each other); and from Glanidium by the lateral line ending near to the caudal peduncle (vs. terminus of lateral line surpassing the caudal-fin origin).