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<br />What is a Cyprinid? <br /> <br />Cyprinids are not always easy to distinguish from <br />other fishes. Basic cyprinid characteristics include <br />no teeth on the jaws, a single dorsal fin, pelvic fins <br />in an abdominal position, pectoral fins low on the <br />side, and no adipose fin. The first full-length ray of <br />the dorsal and anal fins is hardened into a spine-like <br />structure in some foreign cyprinids (for example, the <br />Common Carp, Crucian Carp, and Goldfish). Native <br />North American cyprinids lack a spine-like ray, except <br />certain genera endemic to the desert southwest (such as <br />the Plagopterus, Meda, and Lepidomeda). Cyprinids <br />have 19 principal caudal-fin rays (17 branched, 2 <br />unbranched). The scales are cycloid and the lateral-line <br />system is typically well developed. The head typically <br />has no scales. Cyprinids do not have jaw teeth; instead, <br />they use a pharyngeal apparatus to process food. This <br />apparatus consists of a modified thick fifth pharyngeal <br />arch that bears teeth and a chewing (masticatory) pad <br />that is located on roof of the pharynx. The size and shape <br />of the arch and teeth are closely tied to the diet of the <br />species. The lips usually are thin, but in some cyprinids <br />they are enlarged and sucker-like or even lobed. Most <br />cyprinids lack barbels on the lips but they are present in <br />a few genera, including a few native to North America. <br />A swim (gas) bladder is always present and usually two- <br />chambered. Cyprinids and several related groups have <br />a Weberian apparatus comprised of modified anterior <br />vertebrae that connect the swim bladder to the inner <br />ear. The Weberian apparatus transmits sound vibra- <br />tions to auditory receptors in the brain and is thought to <br />give cyprinids a keen sense of hearing. Most cyprinids <br />have a typical minnow-shaped body form, but some are <br />elongated, some compressed, and others robust. Many <br />cyprinids are sexually dimorphic. For example, males <br />of many species become brightly colored during the <br />breeding season, and may temporarily develop nuptial <br />(breeding) tubercles. Females may also develop breeding <br />tubercles, but these are generally less well developed <br />than those of the males. Proliferation and distribution of <br />tubercles on the body varies between sexes and among <br />species, often appearing on parts of the head, body, and <br />fins (Etnier and Starnes, 1993; Jenkins and Burkhead, <br />1994; Nico and others, 2005). <br /> <br />Introduction 3 <br /> <br />Introduced Versus Native Cyprinids <br /> <br />Because the family is so diverse, there is no single <br />set of characteristics that distinguishes all introduced <br />cyprinids from native North American cyprinids. <br />Nevertheless, a few introduced cyprinids are distinctive <br />and can easily be identified as non-natives. Among these <br />are Common Carp, Goldfish, and Crucian Carp, which <br />have a stout, spine-like ray in the front part of their <br />dorsal and anal fins. Only a few North American species <br />native to the desert southwest possess similar spine-like <br />rays. 1n addition, some foreign cyprinids have relatively <br />long dorsal fins with 13 or more branched rays. 1n <br />contrast, almost all native cyprinids have short dorsal <br />fins, with 11 or fewer (usually 7-9) branched dorsal-fin <br />rays. Moreover, most foreign cyprinids are medium- <br />or large-sized fishes, reaching over a meter long. 1n <br />contrast, the majority of native cyprinids are fairly small <br />and few species exceed 15 cm TL. One notable excep- <br />tion is the native (and critically endangered) Colorado <br />Pikeminnow, a species historically known to reach <br />almost 2 m long and weigh 40 kg (Minckley 1973). <br /> <br />Other Fishes <br /> <br />Only a few other non-cyprinid fishes native to North <br />America are superficially similar to foreign cyprinids. <br />Some members of the sucker family (Catostomidae), <br />such as buffalos (Ictiobus) and carp suckers (Carpiodes), <br />resemble the Common Carp, Goldfish, and Crucian <br />Carp. Suckers share some cyprinid characteristics, . <br />including pharyngeal teeth, cycloid scales, and nuptial <br />tubercles on breeding males. Suckers also lack jaw teeth <br />and adipose fins. However, suckers can be distinguished <br />from cyprinids by the number of principle caudal-fin <br />rays (18 in suckers, 19 in cyprinids). Barbels are pres- <br />ent in some cyprinids, but are always absent in suckers. <br />Additionally, suckers lack spine-like dorsal- and anal- <br />fin rays that are characteristics of the Common Carp, <br />Goldfish, and Crucian Carp. The pharyngeal teeth of <br />suckers are typically long and fine, are arranged in a <br />single comb-like row along the arch, and number 10 <br />or more per side. In cyprinids, the pharyngeal teeth are <br />often (but not always) stout or molar-like, and number <br />less than 10 per side. The mouth of most suckers opens <br />ventrally, and the lips are generally thick and fleshy <br />(Jenkins and Burkhead, 1994). <br />