Sinohesione genitaliphora gen. et sp. n. (Polychaeta, Hesionidae), an interstitial annelid with unique dimorphous external genital organs

Abstract

Sinohesione genituliphoru gcn. ct sp. n. (Polychaeta. Hcsionidac), an intcrstitial annclid with unique dimorphous external genital organs.-Zool. Scr. 23: 95-105.A ncw hcsionid. Sinohesione genitaliphora gcn. ct sp. n.. is dcscribcd from intertidal sandy sediments of Hainan Island, China. It diffcrs from hithcrto known hcsionids by the prcscncc of cxtcrnal genital organs in both sexes. In the malcs thcrc is onc pair of sac-like appendages, cach bearing a tubc-shapcd pcnis, o n chaetigcr 10. In thc fcmalcs thc paircd sac-shepcd orgins arc situated on chaetigcr 12. Reconstructions of scmi-and ultrathin scctions show that ii long, hciivily coilcd spcrm duct opcns at the tip of each pcnis. Thc duct opcns with a ciliated funnel into ii seminal vesicle in chactigcr 9. Prominent gland cclls surround thc spcrm duct for the most part. 'I'hc female genital organs cach havc two opcnings; one of which lcads t o a blind cnding scmin;il rcccptaclc. The othcr is thc cxtcrnal pore of a ciliatcd oviduct that originates as an open funnel in the coclom of chaetigcr 10. Thc functional and phylogcnctic significancc of thcsc structurcs is discussed.

Phylogeny and classification of Hesionidae (Polychaeta)

“…on European Gyptis Marion & Bobretzky in Marion, 1874 andAmphiduros, andWestheide et al (1994) on a new species and genus from China. Hartmann-Schroder (1 97 1) divided the family into the two subfamilies Hesioninae and Microphthalminae, and has described a large number of new taxa in a series of polychaete studies from world-wide areas (Hartmann-Schroder 1959, 1962a, 1962b, 1974a, b, 1980, 1982aHartmann-Schroder & Rosenfeldt 1992).…”

“…Two shapes, though, are considered distinct and well delineated: the short and stout appearance of Hesione (Fig. 4), Leocrates, Leocratides, and Wesenbergia, and the elongated threadlike shape of Heteropodarke Hartmann-Schroder, 1962 and Sinohesione Westheide et al 1994. Ontogenetic information was not applicable as all observed juvenile conditions are separate from the scored adult expressions.…”

Male genital organs in the eulittoral meiofaunal polychaete Stygocapitella subterranea (Annelida, Parergodrilidae): ultrastructure, functional and phylogenetic significance

“…Karling 1958;Giere and Riser 1981, Giere and Erséus 1998, Bührmann et al 1996Kuper and Westheide 1997;Rota 1998;Purschke 2002Purschke , 2005. Whether the vesicles present in Sinohesione genitaliphora Westheide et al, 1994 are of the Wrst or second type awaits additional observations (Westheide et al 1994). However, such spaces are typical of Clitellata, where they may occupy up to three segments (Sawyer 1986;Purschke et al 1993;Purschke 1999).…”

Ultrastructure of the male reproductive organs in the interstitial annelid Sphaerosyllis hermaphrodita (”Polychaeta”, Syllidae)

“…The description of the direct transfer of spermatophores in Hesionides arenaria Friedrich, 1937 (see Westheide and Ax 1965) initiated a long series of investigations on the reproductive biology of meiofaunal "Polychaeta", in which a number of new reproductive structures and modes of direct sperm transfer were discovered (Westheide 1984;Westheide et al 1994), most of them obviously evolved independently. Yet another example is provided by the unique genital anatomy and reproduction of Sphaerosyllis hermaphrodita Westheide, 1990 (Syllidae, Exogoninae).…”