Carpiodes Rafinesque
In 1817, Charles A. LeSueur proposed Catostomus as a new genus under order Abdominales and described eighteen new species, including Catostomus cyprinus from the Elk River and streams entering Chesapeake Bay. LeSueur stated that C. cyprinus was the largest of his Catostomus and resembled the common carp of Europe. In Ichthyologia Ohiensis, Constantine Rafinesque (1820) described twelve new Catostomus and subdivided the genus into five subgenera. Rafinesque defined subgenus Carpiodes as a group characterized by a slighly compressed oblong body, a compressed head, nine abdominal rays, and an elongate, equally-forked tail. He described Catostomus (Carpiodes) carpio as a large carp sucker with a sloping head, rounded snout, small black eyes, a white chin, bluish abdomen, and olivaceous back. He described C. (Carpiodes) velifer as having a silvery eliptical body, accented with golden shades, its dorsal fin looking very much like a large sail. Rafinesque included LeSueur's (1817) Catostomus cyprinus under subgenus Carpiodes.
In 1854, Louis Agassiz elevated the subgenera of Rafinesque to genera and added five new species of Carpiodes. The first, Carpiodes urus, from the Tennessee River, was large (20-30 pounds); its body was neither high nor compressed above as in Carpiodes cyprinus (Agassiz 1854: 356). Carpiodes taurus from the Mobile River, was described as intermediate between C. cyprinus and C. urus in height and compression of the back (Agassiz 1854:355-56). Agassiz described C. bison from the Osage River, Missouri, as more elongate than C. taurus with a smalled head and opercle (Agassiz 1854:356). He described C. vitulus from the Wabash River, Indiana, as the smallest of the new forms with a body form like that of C. taurus. Finally he described C. vacca from the Susquehanna River, a species he felt resembled C. cyprinus more than any other.
In 1855, Agassiz stated that the family of cyprinoids to which Carpiodes and Ictiobus belong, posed a unique problem when attempting to recognize genera, because of the necessity of dissecting specimens in order to identify key features. As a solution he proposed analysis of pharyngeal teeth as a reliable characteriztic for separating genera. In performing this analysis, Agassiz discovered that Carpiodes comprised two distinct groups: those with thin flat pharyngeals with extremely small teeth, and generally possessing high dorsal fins (these he retained in Carpiodes); and those with triangular pharyngeal teeth that gradually increased in size and thickness along the upper margin of the bone, and generally possessing low dorsal fins (these he classified in the new genus Bubalichthys). In this latter group he put C. urus, C. taurus, C. vitulus. Agassiz (1855) further claimed that C. cyprinus comprised three different species: nominal C. cyprinus LeSueur from streams of the middle Atlantic Slope (C. vacca was relegated to its synonymy); C. cyprinus of the Ohio River, which Agassiz believed to be Carpiodes velifer Rafinesque; and a species collected by Zadik Thompson from Lake Champlain and considered native to the "waters of Northern States," which Agassiz (1854) mistakenly called C. cyprinus. He named this later form C. thompsoni (Agassiz 1855: 76) and stated that it was easily differentiated from C. velifer by its smaller, more open angled scales. He considered C. thompsoni and C. velifer to be the shortest bodied C. cyprinus-like forms, C. bison to be the longest, and C. cyprinus intermediate.
Spencer Baird and Charles Girard (1854) described C. tumidus from the Rio Grande near Fort Brown, Texas. In 1857, Girard described Carpiodes damalis as a carp sucker from the upper Missouri with large scales, small pectorals, and a dorsal fin that was much longer than high anteriorly.
Five more species of Carpiodes were added by Edward Drinker Cope in 1870. He described C. difformis from the Wabash River in Indiana, as a medium sized, brownish golden carp sucker having a large eye and a hidden premaxillary bone. The premaxillary was more visible in C. cutisanserinus from the Kiskiminitis River of western Pennsylvania, whose body was the same size as C. difformis but silvery in color. He considered C. selene from the Root River in Michigan, to be intermediate between these two, but with a distinguishable premaxillary bone, a longer muzzle, and its orbit as large as in C. difformis. Cope described C. grayi as a form probably from the western states, with dorsal radii not so long as in C. thompsoni. He described C. nummifer as the largest species in the genus (up to 24 inches), distinguishable by its "exaggerated elongation, the small proportion of its head, and the oliver silver to nickle color of its body" (hence the epithet nummifer which means "money bearer," Cope 1870).
Cope (1870) also divided the genus into two groups based on the form of the dorsal fin and the shape of the muzzle. The first group had highly elevated anterior dorsal rays equalling or exceeding the dorsal base, and a very obtuse muzzle. The second group had shorter dorsals extending to little over half the base length of the fin, and a conic and projecting muzzle. Cope included C. difformis, C. cutisanserinus, and C. selene in the first group, and C. grayi and C. nummifer in the second group.
In Fishes of North and Middle America, Jordan and Evermann (1896) reduced the number of species in Carpiodes by over half. Carpiodes nummifer Cope and C. bison Agassiz were relegated to synonymy of C. carpio Rafinesque. Carpiodes cutisanserinus Cope was relegated to the synonmy of C. difformis Cope. Carpiodes selene was treated as a junior synonym of C. thompsoni Agassiz. Carpiodes velifer Rafinesque - which was known by common names such as quillback, spearfish, and sailfish - was determined by Jordan and Evermann to encompass C. grayi Cope, C. damalis Girard and C. tumidus Baird and Girard. Finally, C. vacca Agassiz was assigned to the synonymy of C. cyprinus (LeSueur). Meek (1904) described Carpiodes microstomus from the Rio Conchos and C. elongatus form the Rio Camacho of Mexico.
Hubbs (1930), restating recommendations he first made in papers appearing the preceding year (Hubbs and Brown 1929, Hubbs and Ortenburger 1929a and b), transfered C. difformis Cope to the synonymy of C. velifer Rafinesque, which he removed from the synonymy of C. cyrpinus LeSueur. C. thompsoni Agassiz was determined by Hubbs to be a synonym of C. cyprinus. He distinguished the large-bodied, elongate form from the Illinois River - which Forbes and Richardson (1908) referred to as C. thompsoni - and renamed it C. forbesi. However, Hubbs (1930: 13) cast doubt on the validity of C. forbesi, stating that it may be a hybrid between C. cyprinus and C. carpio and that he named it for "convenience and emphasis".
Hubbs and Black (1940) studied variation in C. carpio across the range and subdivided the species into western and central (Mississippi Basin) subspecies. They relegated C. elongatus Meek and C. microstomus Meek to the synonymy of C. carpio Rafinesque, retaining C. c. elongatus as a western subspecies of C. carpio (distinguished on the basis of its elongate body form and the weakly developed semitubercular process on tip of the lower jaw) and treating C. microstomus as a junior synonym of C. elongatus.
Milton Trautman (1956) proposed the name C. cyprinus hinei to distinguish the more elongate quillback in the Ohio River Valley, from the deeper bodied form found in Lake Erie (C. c. cyprinus). However, Trautman recognized considerable variation in body form within C. c. cyprinus, which he attributed to differences in water quality. He suggested that an ecomorphic effect might explain the differences in body form he noted between lake and river inhabiting "subspecies" of C. cyprinus. Bailey and Allum (1962) citing Hubb's doubts and Trautman's suggestion shape variation in some Ohio C. cyprinus was ecophenotypic, relegated C. forbesi to the synonymy of C. cyprinus.
