Ultrastructure of spermatogenesis and spermatozoa of Cephalodasys maximus (Gastrotricha, Macrodasyida)

Fischer, Ute

doi:10.1007/bf00416860

Cited by 33 publications

(27 citation statements)

References 11 publications

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“…A distal centriole (basal body) is reported from all studied species of Macrodasyida. Analogue differentiations in the same position can be found in the flagellum of the spermatozoa of some macrodasyidan species, e.g., in Cephalodasys maximus (Fischer 1994) and in species of Urodasys ). There might be, for instance, accessory parts like conical or cap-like structures and thin fibers that support the connection between nucleus and axoneme (Tab.…”

Section: Tab 15: (Continued)supporting

confidence: 52%

“…This pioneering study was shortly followed by an investigation of sperm transfer modalities in an undetermined species of Macrodasys that also contains many data on sperm ultrastructure (Ruppert 1978a). 1.5): Neodasys/Multitubulatina, 1 species (Guidi et al 2003a), Paucitubulatina, 7 species , Balsamo et al 2010a, Guidi et al 2003a, Hummon 1984b, and Macrodasyida, 25 species , Ferraguti & Balsamo 1994, Fischer 1994, 2009, 2011, Pierboni et al 2003, Marotta et al 2005, Pierboni & Kristensen 2007, Ruppert 1978a, Teuchert 1976b, Todaro et al 2000a, 2012a. Since the first investigation of Teuchert (1976b), spermatozoa of at least 33 species from all major subtaxa of the Gastrotricha have been studied ultrastructurally (see Tab.…”

Section: Spermatozoamentioning

confidence: 99%

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1. Gastrotricha

Kieneke¹,

Schmidt‐Rhaesa²

2014

Gastrotricha and Gnathifera

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Section: Tab 15: (Continued)supporting

confidence: 52%

Section: Spermatozoamentioning

confidence: 99%

1. Gastrotricha

Kieneke¹,

Schmidt‐Rhaesa²

2014

Gastrotricha and Gnathifera

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“…The presence in Crasiella of two club-shaped and hollow testes, which extend into sperm ducts confirms the basic plan of the male system of Macrodasyida (Ruppert 1991;Fischer 1994;Guidi et al 2003). However, it has been stated that Lepidodasys sp.…”

Section: Discussionsupporting

confidence: 63%

“…The occurrence of spermatogenesis in a caudo-cephalic and centripetal direction is typical of most Macrodasyida (Hummon and Hummon 1983;Ruppert 1991;Fischer 1994). The major steps in the process have been documented in five species belonging to five families: Turbanella cornuta, Lepidodasys sp., Cephalodasys maximus, Acanthodasys aculeatus and Urodasys anorektoxys (Teuchert 1976;Fischer 1994;Guidi et al 2003Guidi et al , 2004Balsamo et al 2007).…”

Section: Spermatogenesismentioning

confidence: 99%

Reproductive system of the genus Crasiella (Gastrotricha, Macrodasyida)

et al. 2010

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Crasiella diplura from Sweden and Crasiella sp. from Italy were studied alive and with transmission electron microscopy (TEM). The two species are simultaneous hermaphrodites and share the same reproductive system lay-out: paired ovaries extend along the posterior part of the intestine and join mid-dorsally, while bilateral,club-shaped testes lie at the sides of the anterior gut, extending as deferentia that fuse on the mid-ventral plane and open into a single pore; gametes mature in a caudocephalicand centripetal direction. The bulky, sac-like, frontal organ is lined by a simple epithelium and lies dorsolaterally to the intestine, on the left side of the body.The spindle-shaped caudal organ is musculo-glandular and is located ventrolaterally to the gut on the right side. It is characterized by the presence of a roughly Y-shapedinternal channel that opens into two pores close to each other, which function for the intake and outlet of the (auto)sperm, respectively. The spermatozoa, which arepeculiar and similar in the two species, are characterized by a long and complex acrosome consisting of four ultrastructurally distinct regions, three of which findequivalence in other gastrotrich species. The flagellum lacks a striated cylinder. Anatomy and ultrastructure enable us to hypothesize a modality of sperm transfer in Crasiellathat is similar to that observed in Macrodasys

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“…In D. mirabilis, spermatogenesis occurs in a caudo-cephalic direction as in most Macrodasyida (Ruppert 1991;Fisher 1994;Guidi et al 2011). Until now, the major steps of the spermatogenetic process have been documented in six species belonging to six major groups: T. cornuta (Turbanellidae: Teuchert 1976), Lepidodasys sp.…”

Section: Reproductive Anatomy Of Turbanellidaementioning

confidence: 99%

A fresh look at Dinodasys mirabilis (Gastrotricha, Macrodasyida), with focus on the reproductive apparatus and sperm ultrastructure

et al. 2012

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Adults of Dinodasys mirabilis were studied for the first time. The specimens, collected from the west coast of Sweden, were investigated alive and with electron microscopy. Sexually mature specimens attain a total length of 450-490 µm; the adhesive apparatus is made up of anterior, lateral, ventrolateral, dorsal and posterior tubes; one pair of 'cirrata' type tubes is also present. The reproductive apparatus is hermaphroditic; paired testes extend rearward from the pharyngeo-intestinal junction to 3/4 of the trunk; sperm ducts bend anteriorly at U52 and join together into a common, midventral pore at U33. Two ovaries lie along the sides of the caudal intestine, extending anteriorly from U68. Frontal organ present on the right side of the body, centred a U70; caudal organ absent; a gland organ surrounding the terminal intestine may be present but its homology with other organs in a similar position is uncertain. The spermatozoon is a filiform cell, formed by a long acrosome, a spring-like nucleus and a flagellum. The acrosome is divided into two regions: the anterior-most is thin and corkscrew-shaped, the posterior one is rectilinear; both regions are delimited by a continuous external layer of thick, dense material, that in longitudinal section appears obliquely striated and surrounds a long pile of stout, electron-dense cylinders; the nucleus contains condensed chromatin and is coiled around an elongate mitochondrion; the flagellum possesses a 9x2 + 2 axoneme devoid of striated cylinder. Within Macrodasyida, U-bend sperm ducts and the peculiar ultrastructure of the acrosome are characteristics shared by other Turbanellidae studied so far, providing a foundation for the current systematization of Dinodasys

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Ultrastructure of spermatogenesis and spermatozoa of Cephalodasys maximus (Gastrotricha, Macrodasyida)

Cited by 33 publications

References 11 publications

1. Gastrotricha

1. Gastrotricha

Reproductive system of the genus Crasiella (Gastrotricha, Macrodasyida)

A fresh look at Dinodasys mirabilis (Gastrotricha, Macrodasyida), with focus on the reproductive apparatus and sperm ultrastructure

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