Archigetes iowensis sp. n. (Cestoda: Caryophyllaeidae) from Cyprinus carpio L. and Limnodrilus hoffmeisteri Claparede

Abstract

Gravid adults of Archigetes iowensis sp. n. are described from the intestine of the cyprinid fish, Cyprinus carpio L. and from the seminal vesicle of the tubificid oligochaete, Limnodrilus hoffmeisteri Claparede from the Iowa River, Hardin County, U.S.A. A. iowensis occurs in tubificids throughout the year, but infection of carp is strictly seasonal. Cestodes becoming gravid in oligochaetes are believed to represent neotenic procercoids of those found in carp. Adult caryophyllaeid cestodes parasitize certain families of fresh-water teleost fishes and tubificid oligochaetes. The family Caryophyllaeidae was established by Leuckart in 1878. Hunter (1930) recognized four subfamilies: Caryophyllaeinae Nybelin, 1922; Lytocestinae Hunter, 1927; Capingentinae Hunter, 1930; and Wenyoninae Hunter, 1927. Hunter included the family Caryophyllaeidae in the order Pseudophyllidea Cams, 1863, but Wardle and McLeod (1952) elevated it to ordinal rank (Caryophyllidea) and gave the four subfamilies recognized by Hunter familial rank. Yamaguti (1959) retained the order Caryophyllidea (but improperly included it in the Cestodaria), and retained a single family, Caryophyllaeidae, consisting of three subfamilies: Caryophyllaeinae, Capingentinae, and Lytocestinae. Yamaguti reduced the family Wenyonidae to a genus (Wenyonia Woodland, 1923) of the Caryophyllaeinae. In addition to the three subfamilies recognized by Yamaguti, Joyeux and Baer (1961) listed a fourth, Bovieniinae Fuhrmann, 1931. Furthermore, they retained the family Caryophyllaeidae in the order Pseudophyllidea. Eleven genera, including Archigetes Leuckart, 1878 and Biacetabulum Hunter, 1927, are generally assigned to the subfamily Caryophyllaeinae. Received for publication 8 February 1962. This study was supported in part by National Science Foundation Grant G-9022 under the direction of Martin J. Ulmer. Caryophyllaeid cestodes becoming mature or gravid in oligochaetes have been recognized for many years. The genus Archigetes has long been considered as the only cestode group whose members produce eggs while in the invertebrate host. More recently, other caryophyllaeid genera have been described whose members are capable of reaching maturity in tubificids, and may even produce eggs in such hosts. Most species, however, become ovigerous only if they reach suitable fish hosts. The concept of Archigetes as a distinct genus has been questioned by several investigators, who believe that species assigned to this genus are progenetically-developed larvae of other genera, such as Biacetabulum. Unfortunately, the paucity of experimentally-controlled life cycle studies has been a hindrance to the complete understanding of this cestode