Catostomus commersoni (Lacepede, 1803)

Conway, Kevin W., 2011, Osteology of the South Asian Genus Psilorhynchus McClelland, 1839 (Teleostei: Ostariophysi: Psilorhynchidae), with investigation of its phylogenetic relationships within the order Cypriniformes, Zoological Journal of the Linnean Society 163 (5), pp. 50-154 : 118-120

publication ID

https://doi.org/ 10.1111/j.1096-3642.2011.00698.x

persistent identifier

https://treatment.plazi.org/id/03B287ED-FFBA-3756-FC8D-13BB84D4AC3F

treatment provided by

Valdenar

scientific name

Catostomus commersoni
status

 

A. Catostomus commersoni View in CoL

103. Contact between fifth parapophysis and outer arm of the os suspensorium: (0) absent; (1) present (CI = 1.00; RI = 1.00).

In members of the family Cyprinidae and in Psilorhynchus the parapophysis of the fifth vertebral centrum is directed anteriorly, and is in direct contact with the posterior edge of the outer arm of the os suspensorium, at a point close to its base ( Figs 13 View Figure 13 , 36A, B). In other cypriniform fishes and in otophysan outgroup taxa the fifth parapophysis is directed laterally, and is separate from the outer arm of the os suspensorium ( Fig. 36C–H). In non-ostariophysan outgroup taxa the parapophysis of the fifth vertebral centrum is separate from the elements associated with the fourth centrum.

104. Lateral process of the first vertebral centrum: (0) absent or, when present, short; (1) elongate, projecting well into somatic musculature (CI = 0.25; RI = 0.50).

In members of the Nemacheilidae the first centrum bears a large lateral process that extends laterally along the anterior edge of the lateral process of the second vertebral centrum ( Sawada, 1982). A similar situation is present in members of the family Gyrinocheilidae ( Bird & Hernandez, 2007; Fig. 36D) and in Carpiodes cyprinus . In other cypriniform fishes and otophysan outgroup taxa that possess a lateral process on the first vertebral centrum, the lateral process is short and does not extend far from the centrum ( Fig. 36A–C, E–G).

105. Fifth rib: (0) without large cup-shaped depression on anterior edge; (1) with large cup-shaped depression on anterior edge (CI = 1.00; RI = 1.00).

In Psilorhynchus a large cup-shaped depression is present along the anterior edge of the fifth rib in males only ( Fig. 12A–E View Figure 12 ). In other cypriniform fishes and in outgroup taxa the fifth rib is slender, and lacks a cup-shaped depression along its anterior edge ( Fig. 36).

106. Post-Weberian process: (0) absent; (1) present (CI = 1.00; RI = 1.00).

In Psilorhynchus the outer arm of the os suspensorium is fused with its antimere posteriorly, in males only, and extends posteriorly, past the Weberian centra, ventral to the vertebral column, terminating below the sixth vertebral centrum ( Fig. 12A–E View Figure 12 ). In other cypriniform fishes and otophysan out-groups such sexual dimorphism of the outer arm of the os suspensorium is absent ( Fig. 36). This character is inapplicable to nonotophysan out-group taxa.

107. Intercalarium: (0) base with contact to vertebral column; (1) base without contact to vertebral column (CI = 0.50; RI = 0.95).

In all members of the Cobitoidea , excluding members of the Catostomidae , the intercalarium is a small nodule of bone that lacks contact with the second vertebral centrum ( Bird & Hernandez, 2007; Fig. 36D–H). In other cypriniform fishes and otophysan outgroup taxa the intercalarium is in contact with the second vertebral centrum ( Figs 12 View Figure 12 , 36A–C). In Vaillantella the intercalarium is a thin splintshaped element that contacts the neural arch of the third vertebral centrum dorsally ( Fig. 36F). Its base, however, is without contact with the second vertebral centrum and as such this taxon was considered to exhibit the derived condition, and was coded as such. This character is inapplicable to non-otophysan outgroup taxa.

108. Os suspensorium: (0) not surrounding anterior swim-bladder chamber; (1) completely surrounding anterior swim-bladder chamber (CI = 1.00; RI = 1.00).

In members of the family Cobitidae the outer arm of the os suspensorium completely surrounds the anterior chamber of the swim bladder, forming a gourd-like capsule ( Sawada, 1982; Fig. 36G). In other cypriniform taxa in which the anterior swim-bladder chamber is encapsulated, the capsule is formed anteriorly by the lateral process of the second vertebral centrum ( Figs 11 View Figure 11 , 12 View Figure 12 , 36H). This character is inapplicable to non-otophysan outgroup taxa.

PAIRED FIN GIRDLES

109. Bony contact between anteriormost point of coracoid and cleithrum ( Sawada, 1982: character 37): (0) present; (1) absent (CI = 1.00; RI = 1.00).

In members of the Cobitidae , excluding Acantopsis , the anteriormost point of the coracoid does not contact the cleithrum ( Sawada, 1982; Fig. 38F). In other cypriniform fishes and in outgroup taxa the anteriormost point of the coracoid is in contact with the anteromedial face of the coracoid ( Fig. 38A–E, G).

110. Post-temporal ( Sawada, 1982: character 34): (0) present; (1) absent (CI = 1.00; RI = 1.00).

In members of the genus Psilorhynchus the posttemporal is absent and the pectoral girdle articulates with the neurocranium dorsally via the supracleithrum ( Fig. 18). In other cypriniform fishes and in outgroup taxa the post-temporal is present ( Figs 38, 39 View Figure 39 ). Contrary to Sawada (1982), a very small posttemporal is present in the single specimen of Annamia normani that was examined ( Fig. 39B View Figure 39 ).

111. Postcleithrum ( Fink & Fink, 1981: character 96; Sawada, 1982: character 35): (0) more than one; (1) one; (2) absent (CI = 0.25; RI = 0.77).

In the majority of cypriniform fishes a single, slender rod-shaped postcleithrum articulates with the medial face of the cleithrum ( Fink & Fink, 1981; Fig. 38A–E). In members of the genus Psilorhynchus ( Fig. 18), all members of the Cobitidae ( Fig. 38F), certain members of the Balitoridae ( Fig. 38H), certain members of the Nemacheilidae ( Fig. 38G), Vaillantella euepiptera , and Garra dembeensis (Rüppell, 1835) , the postcleithrum is absent. The number of postcleithra is variable amongst outgroup taxa examined, with anywhere between one, as in Denticeps clupeoides ( Greenwood, 1968) and Hiodon alosoides ( Hilton, 2002) , and six, as in Elops cf. senegalensis ( Arratia, 1997) .

112. Cleithrum ( Sawada, 1982): (0) well separted from vertebral elements; (1) closely associated with lateral process of second vertebral centrum (CI = 1.00; RI = 1.00).

In members of the family Balitoridae the posteriormost edge of the cleithrum is tightly bound to the anterior edge of the gas-bladder capsule ( Sawada, 1982). In other cypriniform fishes and in out-group taxa the cleithrum is without contact with vertebral elements.

113. Number of pectoral radials ( Sawada, 1982; character 36): (0) four; (1) three (CI = 0.33; RI = 0.71).

In members of the family Cobitidae , the nemacheilid Barbatula barbatula , and the out-group taxon Denticeps clupeoides , pectoral radial 4 is absent ( Greenwood, 1968; Sawada, 1982; Fig. 38F). In other cypriniform fishes and the remaining outgroup taxa pectoral radial 4 is present ( Figs 18, 38A–E, G, H).

114. Baudelot’s ligament: (0) ligamentous; (1) with ligamentous ossification (CI = 0.50; RI = 0.50).

In members of the Gyrinocheilidae and Carpiodes cyprinus Baudelot’s ligament contains a ligamentous ossification that extends along the length of the ligament from its origin on the tip of the lateral process of the first vertebral centrum to its point just medial to its point of contact with the cleithrum. In other cypriniform fishes and in outgroup taxa Baudelot’s ligament does not exhibit a ligamentous ossification. Baudelot’s ligament could not be located in any member of Psilorhynchus examined.

115. Cleithral–occipital ligament: (0) absent; (1) present (CI = 1.00; RI = 1.00).

In members of the families Botiidae , Cobitidae , Balitoridae (excluding the two species of Homaloptera examined), Nemacheilidae, and Vaillantella a strong ligament originates on the exoccipital and inserts on the dorsomedial edge of the cleithrum ( Fig. 39B View Figure 39 ). In other cypriniform fishes and in outgroup taxa there is no such ligament between the cleithrum and the exoccipital ( Fig. 39A View Figure 39 ).

116. Pectoral radial 3: (0) without dorsally directed process proximally; (1) with dorsally directed process proximally (1). (CI = 1.00; RI = 1.00).

In P. gracilis , P. robustus , and P. melissa the dorsal surface of pectoral radial 3 bears a prominent dorsally directed process proximally ( Figs 18D, E, 19D, E View Figure 19 ). In other cypriniform fishes and in outgroup taxa the dorsal surface of pectoral radial 3 is relatively flat ( Figs 18A–C, F, 19A–C, F View Figure 19 , 38).

117. Rib associated with pelvic splint ( Sawada, 1982: character 45): (0) similar in shape to other ribs; (1) greatly thickened and robust (CI = 0.33; RI = 0.60).

In members of the Balitoridae the rib associated with the pelvic splint is greatly thickened in comparison with other ribs ( Sawada, 1982). A similar condition is also present in members of Psilorhynchus ( Fig. 15 View Figure 15 ) and Garra dembeensis , although in these latter cases the difference in thickness between the rib associated with the pelvic splint and other ribs is not as pronounced as it is in members of the Balitoridae . In other cypriniform fishes and in outgroup taxa the rib associated with the pelvic splint is similar in thickness to other ribs.

MEDIAN FINS AND SUPPORTING SKELETON

118. Third unbranched dorsal fin ray ( Chen et al., 1984, in part): (0) segments of each hemitrich

Darwin Core Archive (for parent article) View in SIBiLS Plain XML RDF