Chinchaysuyoa, Marceniuk & Marchena & Oliveira & Betancur-R, 2019

Marceniuk, Alexandre Pires, Marchena, Jose, Oliveira, Claudio & Betancur-R, Ricardo, 2019, Chinchaysuyoa, a new genus of the fish family Ariidae (Siluriformes), with a redescription of Chinchaysuyoa labiata from Ecuador and a new species description from Peru, Zootaxa 4551 (3), pp. 361-378 : 364-365

Chinchaysuyoa new genus

Type species. Chinchaysuyoa labiata .

Diagnosis. The Parsimony Analysis ( Fig. 1a ) was used to recognize the derived characters supporting Chinchaysuyoa . Morphological synapomorphies are represented by 13 derived conditions acquired independently in other ariid genera: (1) bony bridge formed by lateral ethmoid and frontal cylindrical and thin, Marceniuk et al. (2012: 16), convergent in Arius gagora , Arius arius , Arius maculatus , Arius oetik , A. madagascariensis , Aspistor , Cathorops , Cephalocassis , Cinetodus , Cryptarius , Doiichthys , Hemiarius , Nedystoma , Nemapteryx , Notarius , Pachyula , Potamarius grandoculis , P. usumacintae , and Potamosilurus ; (2) vomer anterior margin very pronounced and acute, Marceniuk et al. (2012: 48), convergent in Arius , Amissidens , Aspistor , Cephalocassis , Cinetodus , Notarius (except N. planiceps and N. cookei ), Osteogeneiosus , Pachyula , Plicofollis , Potamarius , except P. usumacintae , and Potamosilurus , except P. velutinus ); (3) Accessory tooth plates small, transversely elongate and narrow, Kailola (2003: 50), Marceniuk et al. (2012: 58), convergent in Bagre , Cochlefelis , Galeichthys , Neoarius , Potamosilurus latirostris , and Sciades leptaspis ; (4) optic foramen very large, Marceniuk et al. (2012: 65), convergent in Cephalocassis , Doiichthys , Nedystoma , and Nemapteryx ); (5) anterior aortic canal opening at base of subvertebral process and anteroventrally oriented, Marceniuk et al. (2012: 70), convergent in Arius , Aspistor , Batrachocephalus , Cephalocassis , Cinetodus , Cryptarius , Doiichthys , Hemiarius , Ketengus , Nedystoma , Nemapteryx , Notarius , Osteogeneiosus , Pachyula , Plicofollis , Potamosilurus ); (6) posterior process of exoccipital sutured to Müllerian ramus, Marceniuk et al. (2012: 86), convergent in Ariopsis , Potamarius , and Sciades ( Fig. 3A ); (7) half or less of interopercle posterior face contacting ventral margin of opercle, Marceniuk et al. (2012: 124), convergent in Batrachocephalus , Cochlefelis , Ketengus , Neoarius , Notarius , Sciades , except S. herzbergii and S. couma , Plicofollis platystomus ); (8) anterior portion of interopercle compressed and bifurcate, Marceniuk et al. (2012: 125), convergent in Cathorops and Plicofollis ( Fig. 3b , see Fig. 15 in Marceniuk et al. 2012); (9) interopercle anterior portion conspicuously narrow, Marceniuk et al. (2012: 126), convergent Brustiarius , Cephalocassis , Doiichthys , and Nedystoma ( Fig. 3b , see Fig. 15 in Marceniuk et al. 2012); (11) metapterygoid one and a half times longer than deep in perpendicular section, Marceniuk et al. (2012: 128), convergent in Cathorops dasycephalus , Cephalocassis , Cinetodus , Cryptarius , Pachyula , and Plicofollis , Potamarius grandoculis , P. izabalensis ); (12) uncinate process of third epibranchial much longer and wider than mesial portion of third epibranchial delimited by uncinate process, Marceniuk et al. (2012: 175), convergent in Plicofollis ( Fig. 3c , see Fig. 23 in Marceniuk et al. 2012); (13) posterior process of cleithrum very long, Kailola (2004: 14), Marceniuk et al. (2012: 214) convergent in Cinetodus and Pachyula ( Fig. 3d , see Fig. 27 in Marceniuk et al. 2012); (14) swim bladder with two chambers, Marceniuk et al. (2012: 227), convergent in Notarius grandicassis ( Fig. 3e , see Fig. 1 in Marceniuk & Birindelli 2010).

Additional morphological characters that diagnose the new genus from its New World relatives. cephalic shield granulated visible under the skin (vs. cephalic shield smooth, covered by muscle and scarcely visible under the skin in Bagre and Galeichthys ); medial groove of neurocranium present (vs. absent in Amphiarius , Aspistor and Notarius ); posterior cranial fontanel present (vs. absent in Ariopsis , and Sciades ); temporal fossa present and large (vs. absent or very reduced Ariopsis , Cathorops , Occidentarius , Genidens , and Sciades ); vomerine tooth plates absent (vs. present in Ariopsis , Aspistor , Genidens , Notarius , Occidentarius , Sciades ); accessory tooth plates very small (vs. large all other genera except Potamarius ); maxillary barbel fleshy and cylindrical (vs. compressed in Bagre ); two pairs of mental barbels (vs. one pair in Bagre ); base of adipose fin moderately long, as long as anal-fin base (vs. long or very short in Amphiarius , Aspistor, Bagre , Cathorops , and Notarius ); posterior cleithral process distinct from second dorsal process of cleithrum (vs. indistinct in Galeichthys ); posterior cleithral process very long (vs. very short or moderately long in all other genera).

Etymology. Chinchaysuyoa name of the Inca Empire territory that comprised the Ecuador and Peru, gender feminine.

Figures

FIGURE 1. Phylogenetic tree inferred from combined evidence from molecular and morphological data based on Parsimony Analysis (A), Bayesian inference (B) and Maximum Likelihood (C), with bootstrap values greater than 50%. In red, neotropical freshwater species, included in Potamarius sensu Marceniuk & Menezes (2007).

FIGURE 3. Derived conditions in Chinchaysuyoa. (A) posterior process of exoccipital; (B) Anterior portion of interopercle; (C) Uncinate process of third epibranchial; (D) Posterior process of cleithrum; (E) Swimbladder. Abbreviations: ac, anterior chamber; ap, anterior portion; Bs, Basioccipital; Ex, Exoccipital; Mr, Müllerian ramus; pc, posterior chamber; pp, posterior process; up, uncinate process.