Hypostomus cochliodon

Jonathan W. Armbruster, 2003, The species of the Hypostomus cochliodon group (Siluriformes: Loricariidae)., Zootaxa 249, pp. 1-60: 4-5

publication ID

z00249p001

publication LSID

lsid:zoobank.org:pub:DDFAA9D6-E4FA-4C3C-9749-CF0313D30F3C

persistent identifier

http://treatment.plazi.org/id/9366E1A6-75D8-472F-3755-0BBE31106656

treatment provided by

Thomas

scientific name

Hypostomus cochliodon
status

 

[[ Hypostomus cochliodon  ZBK  Group ]]

Introduction

With 650 species currently considered valid (Eschmeyer 2003), the Loricariidae  is the most speciose family of catfishes in the world. Loricariids are typically algivorous or detritivorous, but the Hypostomus cochliodon  ZBK  group (formerly the genus Cochliodon Kner  ) and Panaque Eigenmann  ZBK  are unique among fishes in that they consume wood (Schaefer & Stewart 1993; Nelson et al. 1999). The H. cochliodon  ZBK  group and Panaque  ZBK  share the derived presence of large, spoon-shaped teeth; however, they are unrelated and are placed in two different tribes, the Hypostomini and the Ancistrini  , respectively (Armbruster 1997; in press).

The original description of Cochliodon  was by Heckel (in Kner 1853), but the genus was described in the synonymy of Hypostomus Lacepede  ZBK  . Eigenmann (1922) described Cheiridodus  ZBK  and separated the genus from Cochliodon  based on the presence of a small medial tooth cusp (vs. medial cusp absent). Most loricariids have bicuspid teeth (Muller & Weber 1992), and the presence of a mesial cusp represents a plesiomorphic characteristic within the Loricariidae  . Cochliodon  do actually have a small mesial cusp, but this cusp is occasionally fused into the lateral cusp and visible as a darker, thicker ridge on the tooth (pers. obs.). Isbrücker (1980) recognized Cheiridodus  ZBK  as a synonym of Cochliodon  , but did so without comment. Armbruster (1997; in press) provided a phylogeny for the species of the Hypostominae  based on morphology and determined that Cochliodon  is derived from Hypostomus  ZBK  . In addition, Montoya-Burgos et al. (1998) found Cochliodon  to be related to Hypostomus  ZBK  based on sequences of the 12s and 16s rRNA genes, Montoya-Burgos et al. (2002) found Cochliodon  to be nested within Hypostomus  ZBK  based on sequence data from the mitochondrial D-loop, and Zawadzki (pers comm.) has found Cochliodon  to be derived from Hypostomus  ZBK  based on allozymes. Armbruster (1997, in press) recognized Cochliodon  as a synonym of Hypostomus  ZBK  and refers to the species formerly in Cochliodon  as the H. cochliodon  ZBK  group. Weber and Montoya-Burgos (2002) and Montoya-Burgos et al. (2002) also placed Cochliodon  in the synonymy of Hypostomus  ZBK  .

The Hypostomus cochliodon  ZBK  group has received little attention from authors except for original species descriptions. The seven currently accepted species of the H. cochliodon  ZBK  group are distributed in the Orinoco, Amazon, Essequibo, Magdalena, Paraguay, and Atrato river basins and in the Lake Maracaibo basin (Lilyestrom 1984; Armbruster & Page 1997). There has only been one modern attempt to examine the species of the H. cochliodon  ZBK  group. Lilyestrom (1984) provides descriptions of the species of the H. cochliodon  ZBK  group in Venezuela, a key to all of the species of the H. cochliodon  ZBK  group, and places Cochliodon pospisili Schultz  ZBK  into the synonymy of H. hondae  . The characteristics used in Lilyestrom’s key are mostly proportions and tooth counts and do not adequately separate the species of the H. cochliodon  ZBK  group (pers. obs.). Armbruster and Page (1997) redescribe Rhinelepis levis Pearson  ZBK  , and place the species in Cochliodon  . Hypostomus levis  is unique among the H. cochliodon  ZBK  group in the absence of an adipose fin. Weber and Montoya-Burgos(2002) describe H. fonchii  ZBK  and suggest that it is related to the H. cochliodon  ZBK  group; however, they present no credible evidence for this assertion and H. fonchii  ZBK  is not considered to be part of the H. cochliodon  ZBK  group in this study.

Placing Cochliodon  into the synonymy of Hypostomus  ZBK  is further supported by two species described herein. Hypostomus hemicochliodon  ZBK  and H. sculpodon  ZBK  predominantly eat wood, but do not have spoon-shaped teeth. These species have teeth that appear to be intermediate between other Hypostomus  ZBK  and other species of the H. cochliodon  ZBK  group (Fig. 1) and also appear to eat less wood than the other species of the H. cochliodon  ZBK  group (pers. obs. based on gut contents). Although many other Hypostomus  ZBK  will occasionally consume small amounts of wood, wood only amounts to a very small fraction of the diet (pers. obs.). In this manuscript all species of the H. cochliodon  ZBK  group are redescribed, four new species of the H. cochliodon  ZBK  group are described, and distribution maps, a key, and a phylogeny for the species of the H. cochliodon  ZBK  group is provided.