Spermatogenesis and Spermatozoa in Stygocapitella subterranea (Annelida, Parergodrilidae), an Enigmatic Supralittoral Polychaete

  title={Spermatogenesis and Spermatozoa in Stygocapitella subterranea (Annelida, Parergodrilidae), an Enigmatic Supralittoral Polychaete},
  author={G{\"u}nter Purschke and Mary C. Fursman},
The intertidal polychaete species Stygocapitella subterranea (Parergodrilidae) is characterised by extraordinary biology and morphology, resembling those of clitellates and Hrabeiella periglandulata, a terrestrial species of Annelida. An ultrastructural study of the spermatogenesis and spermatozoa was undertaken to elucidate whether these similarities might exhibit adaptive characters typical of annelids with highly derived reproductive modes. A second goal was to find out whether there are… 

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Delimitation of cryptic species drastically reduces the geographical ranges of marine interstitial ghost-worms (Stygocapitella; Annelida, Sedentaria).
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Vergleichende Ultrastrukturuntersuchungen der Eu- und Paraspermien von 13Protodrilus-Arten (Polychaeta, Annelida) und ihre taxonomische und phylogenetische Bedeutung
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The ultrastructure of the spermatozoon of the oligochaetoid polychaete Questa sp. (Questidae, Annelida) and its phylogenetic significance
Elongation of the primary vesicle and of the mitochondrial derivatives, and presence of an extensive axial rod, are seen in sperm of protodrilid archiannelids with which questids have somatic similarities indicative of a relationship closer than with other annelids.
Ultrastructure of the spermatozoa of Parenterodrilus taenioides (Protodrilida: “Polychaeta”) and its phylogenetic significance
An ultrastructural study revealed that the similar structure of sperm suggests that sperm transfer and fertilization are very probably the same in P. taenioides as in Protodrilus.
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Spermatogenesis and sperm ultrastructure in the interstitial syllid Petitia amphophthalma (Annelida, Polychaeta)
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Sperm ultrastructure and spermatogenesis in the interstitial polychaete Sphaerosyllis hermaphrodita (Syllidae: Exogoninae)
The mature spermatozoa of Sphaerosyllis hermaphrodita (Polychaeta: Syllidae) were reconstructed from electron micrographs, identifying them as belonging to the modified sperm type often found in interstitial polychaetes.
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The absence of synapomorphies with the spermatozoa of the clitellate species corroborates the view that the Aeolosomatidae are not closely related to these taxa.
An ultrastructural investigation of Hrabeiella Pizl & Chalupský, 1984 (Annelida). II. The spermatozoon.
None of the spermatozoal autapomorphies of the Euclitellata is shared by Hrabeiella, and none of the observed similarities to the sperm (introsperm) of questids, protodrilids or other polychaetes seems to represent an immediate synapomorphy.