Phylogenetic analysis of the loricariid subfamily Hypoptopomatinae (Pisces: Siluroidei: Loricariidae), with comments on generic diagnoses and geographic distribution

Abstract

A survey of 55 osteological and myological features provided the basis for a phylogenetic analysis of the genera of the loricariid subfamily Hypoptopomatinae. Eleven genera are recognized. Aceslridium, Hypoptopoma, Microlepidogaster, Otocinclus (sensu stricto), Otothyris, Oxyropsis, Par otocinclus, Pseudotocinclus, Schizolecis and an unnamed new genus from Venezuela are each hypothesized as monophyletic on the basis of at least one uniquely derived, unreversed character stale. Pseudotothyris is diagnosed by one character state representing evolutionary convergence. Otocinclus, as presently defined (Isbriicker, 1980), is paraphyletic. Species related to Otocinclus vestitus, the type species, are more closely related to other Hypoptopomatinae than to other Otocinclus species. The hypothesis of generic relationships described herein is based on the consensus among three equally parsimonious trees of length 89 steps (c = 0.652). Distribution of character states on that tree and character‐state evolution are discussed in terms of support for each lineage. Thirty‐three trees were found one step longer (length = 90, c = 0.644) than the shortest, most parsimonious trees. The consensus among these 33 trees revealed two additional unresolved polychotomies involving members of the tribe Otothyrini and a clade composed of Hypoptopoma, Oxyropsis and Aceslridium. A preliminary framework for the analysis of historical biogeography of the Hypoptopomatinae is discussed.

Taxonomic revision and phylogenetic relationships of Dasyloricaria Isbrücker & Nijssen, 1979 (Siluriformes: Loricariidae), with description of a new species

“…Shape of the parasphenoid (Schaefer, 1991). The parasphenoid of loricariids is generally narrow along its entire length (Schaefer, 1987(Schaefer, , 1991Rapp Py-Daniel, 1997;Armbruster, 2004;Lehmann A., 2006;Pereira, 2008), as observed in Dasyloricaria paucisquama (state 0).…”

“…The parasphenoid of loricariids is generally narrow along its entire length (Schaefer, 1987(Schaefer, , 1991Rapp Py-Daniel, 1997;Armbruster, 2004;Lehmann A., 2006;Pereira, 2008), as observed in Dasyloricaria paucisquama (state 0). Alternatively, the parasphenoid of Sturisoma, D. latiura and D. filamentosa is broad posteriorly at its area of articulation with the basioccipital (state 1).…”

“…In the basal condition, the lateral line terminates one to four plates before the supracaudal plates (state 0). In most loricariids, however, the lateral line extends to the last lateral plate before the supracaudal plates (Schaefer, 1991;state 1). Alternatively, the lateral line continues onto the supracaudal plates in most loricariines (state 2; Fig.…”

“…10a). In a few taxa the crest is reduced and shorter than one-half the length of the bone (Schaefer, 1991; state 1).…”

“…Extension of the lateral line (Schaefer, 1991;character 45). The length of the lateral line is variable among the examined taxa.…”