<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).
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