A taxonomic review of the vampire catfish genus Paracanthopoma Giltay, 1935 (Siluriformes, Trichomycteridae), with descriptions of nine new species and a revised diagnosis of the genus

A taxonomic revision is presented of the genus Paracanthopoma, probably the least-known vandelliine genus at present. The work is based on most of the material available in museums worldwide and includes a major expansion in the knowledge about the genus. Paracanthopoma is circumscribed as a monophyletic group on the basis of nine putatively synapomorphic characters. Evidence is provided for Paracanthopoma and Paravandellia as sister groups and the two genera are comparatively diagnosed. A total of 13 species are recognized in Paracanthopoma, of which nine are new and one is transferred from Paravandellia: Pc. ahriman, new species, Pc. alleynei (Henschel et al., 2021), Pc. carrapata, new species, Pc. cangussu Henschel et al., 2021, Pc. capeta, new species, Pc. daemon, new species, Pc. irritans, new species, Pc. malevola, new species, Pc. parva Giltay, 1935, Pc. saci Dagosta & de Pinna, 2021, Pc. satanica, new species, Pc. truculenta, new species, and Pc. vampyra, new species. Different species display a high degree of phenotypic divergence and are diagnosed on the basis of traditional as well as new morphological characters of both external and internal anatomy. Geographical distributions are mapped for each species and an identification key is provided. Preliminary evidence suggests the existence of four main subclades within Paracanthopoma. The first one includes Pc. ahriman, Pc. cangussu, and Pc. irritans. A second subclade comprises Pc. carrapata, Pc. daemon, Pc. parva, and Pc. truculenta. A third clade includes Pc. malevola and Pc. satanica and a fourth comprises Pc. alleynei and Pc. vampyra. The last clade lacks some putative synapomorphies of all other members of Paracanthopoma and seems to be the sister group to the rest of the genus. Relationships of Pc. capeta and Pc. saci are not as clear, but some evidence exists for the former being related to the first subclade and the latter to the second subclade

Two new catfish species of typically Amazonian lineages in the Upper Rio Paraguay (Aspredinidae: Hoplomyzontinae and Trichomycteridae: Vandelliinae), with a biogeographic discussion

Two new species of particular biogeographic significance are described from the upper rio Paraguay basin, one of the genus Paracanthopoma (Trichomycteridae, Vandelliinae) and the other of the genus Ernstichthys (Aspredinidae, Hoplomyzontinae). The two species occur sympatrically in the Rio Taquarizinho, tributary of the Rio Taquari, in the upper Paraguay system. Paracanthopoma saci is distinguished from its only congener, P. parva, by a spatulate caudal peduncle; a minuscule premaxillary dentition (reduced to three delicate teeth); the supraorbital latero-sensory canals opening as two separate s6 pores; the caudal fin slightly convex or truncate with round edges; the skull roof entirely open, unossified; the origins of dorsal and anal fins approximately at same vertical; and the pelvic fin with three rays. Ernstichthys taquari is diagnosed among congeners by the narrow bony shields on dorsal and ventral series, not overlapping or contacting each other; by the presence of seven or eight serrations on the posterior margin of the pectoral spine; and by the pectoral-fin spine only slightly larger than subsequent soft rays. Both Paracanthopoma and Ernstichthys were previously unknown outside of the Greater Amazonian river systems (Amazon, Orinoco, Essequibo and smaller surrounding drainages). Their presence restricted to the Rio Taquari is unexpected and suggests a peculiar biogeographical history. Ancestral geographic distributions were reconstructed using S-DIVA and BBM methods in RASP. A majority of resulting hypotheses support that the two species reached the Paraguay from the Amazon. The alternative explanation accounts for their presence in the Paraguay by vicariant events. In no case, their presence in the Paraguay is an ancestral distribution with subsequent Amazonian dispersal. Though unusual, this pattern is also seen in a few other fish taxa, showing that the Rio Taquari is biogeographically hybrid, combining elements from both the Paraguay and Amazon drainages

A new family of neotropical freshwater fishes from deep fossorial amazonian habitat, with a reappraisal of morphological characiform phylogeny (Teleostei: Ostariophysi)

We present the taxonomic description of Tarumaniidae, a new family of South American freshwater fishes including a new genus (Tarumania) and species (Tarumania walkerae) from the Central Amazon. The new taxon displays an extraordinary set of unique characteristics, which sets it apart from all other known bony fishes, either in South America or elsewhere. Tarumaniidae has reverse-imbricated scales on the head, 244 or more scales along the midlateral lateral series, an 11-chambered swimbladder extending along most of the body, an anteriorly deflectable pelvic fin and a platybasic skull, among other unusual traits. Although the general habitus of Tarumania gives little hint of its phylogenetic placement, examination of internal anatomy is largely elucidative concerning the main features of its relationships. For example, Tarumania has a complete Weberian apparatus, comprising a set of characteristics supporting its position in Otophysi and Ostariophysi. Additional comparative evidence corroborates its placement in the order Characiformes, including some trademark characiform synapomorphies such as the presence of a hypertrophied lagenar capsule. We conducted a phylogenetic analysis on the basis of previously published morphological evidence for Characiformes, with the inclusion of Tarumania and additional relevant taxa and characters. Results support the position of Tarumania as a part of the superfamily Erythrinoidea and sister group to the neotropical Erythrinidae. Our increased taxonomic representation of Erythrinidae in the matrices firmly corroborates Tarumania as sister group to the whole of Erythrinidae and not to a subgroup of that family. Tarumania walkerae is a predator, which inhabits vast leaf-litter deposits in the Rio Negro drainage, and is found deeply buried in isolated pools during the dry season. It is the first characiform with an anguilliform body shape and fossorial habits. The unprecedented combination of phenotypic traits, behaviour and habitat adds substantially to the larger picture of freshwater fish diversity. Although its microhabitat is difficult to sample, the geographical range of T. walkerae includes areas close to major urban centres and which have been ichthyologically surveyed for many years. The fact that a relatively large and highly distinctive fish such as Tarumania remained undiscovered until now is testimony to the still-incomplete state of knowledge of biodiversity in Amazonian waters. © 2017 The Linnean Society of London, Zoological Journal of the Linnean Society

Poor taxonomic sampling undermines nomenclatural stability: A reply to Roxo et al. (2019)

Reis, Roberto E., Britski, Heraldo A., Britto, Marcelo R., Buckup, Paulo A., Calegari, Bárbara B., Camelier, Priscila, Delapieve, Maria Laura S., Langeani, Francisco, Lehmann, Pablo, Lucinda, Paulo H. F., Marinho, Manoela, Martins, Fernanda O., Menezes, Naércio A., Moreira, Cristiano R., De Pinna, Mário C. C., Pavanelli, Carla S., Rapp Py- Daniel, Lucia H., Sousa, Leandro M. (2019): Poor taxonomic sampling undermines nomenclatural stability: A reply to Roxo et al. (2019). Zootaxa 4701 (5): 497-500, DOI: https://doi.org/10.11646/zootaxa.4701.5.1