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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2004-10-20
pubmed:abstractText
In Tubificidae, the male genital duct comprises a funnel in the testes segment, followed by a vas deferens, an atrium, and, frequently, a copulatory structure in the adjacent ovarian segment. There may also be a diffuse or compact prostate gland in association with the duct. The morphology and position of the genital ducts are important for the classification of the oligochaetous Clitellata. Different parts of the male duct, however, have been named without regard to whether they are homologous or not. One way to establish better hypotheses of homology is to study the detailed morphology and/or the development of the genital ducts. The morphogenesis of the genital ducts in Alexandrovia onegensis (Telmatodrilinae) is described. The male funnel originates by multiplication of peritoneal (mesodermal) cells in the posterior septum in the testes segment. A cord of these cells breaks through the septum and grows backwards into the next segment, where it connects to the epidermis. This cord gives rise to the vas deferens, and is therefore mesodermal in origin. The atrium in A. onegensis develops from a primary epidermal (ectodermal) invagination. The vas deferens and atrium connect and a continuous duct from the testes segment to the exterior is formed. Several compact prostate glands develop along the atrium, each being formed from cells in the atrial epithelium. The spermatheca develops from an invagination of the epidermis in the testes segment. The female duct is formed from peritoneal (mesodermal) cells in the posterior septum in the ovarian segment. These developmental findings strengthen the hypothesis about a closer relationship between the Telmatodrilinae and Tubificinae (both Tubificidae).
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0362-2525
pubmed:author
pubmed:issnType
Print
pubmed:volume
262
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
791-9
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Development of the genital ducts in Telmatodrilinae (Tubificidae, Clitellata).
pubmed:affiliation
Department of Invertebrate Zoology, Swedish Museum of Natural History, SE-104 05 Stockholm, Sweden. lena.gustavsson@nrm.se
pubmed:publicationType
Journal Article