Abstract

Sperm morphology was examined in 42 species of Thoracica, from 32 genera in 11 families, and in one species of Acrothoracica. The filiform spermatozoa of Thoracica, Acrothoracica and Rhizocephala share: (1) an axoneme capped by a conical acrosome; (2) a filiform nucleus running parallel to the axoneme; (3) an elongate mitochondrion posterior to the nucleus; (4) glycogen deposits. This sperm type links the Thoracica, Acrothoracica and Rhizocephala and distinguishes them from the other Thecostraca. Structural differences in the sperm nucleus separate the three groups and are further consistent with segregation of the Rhizocephala from the Thoracica + Acrothoracica (= Cirripedia sensu Newman). In spermatozoa from seminal vesicles of Thoracica, an accessory droplet is usually present. This structure, produced by the Golgi complex during spermiogenesis, shows variation among species in its form and internal substructure. The Iblidae, Lepadidae and Scalpellidae have distinctive modifications of the accessory droplet. Among the scalpellids, the Pollicipedinae retain a generalised thoracican sperm morphology, while other subfamilies which have been studied (Lithotryinae, Scalpellinae, Calanticinae) display differing modifications of nuclear and droplet structure. Sperm morphology of Verruca is consistent with derivation of the Verrucomorpha from scalpelloids related more closely to the Pollicipedinae than to the Calanticinae, Lithotryinae or Scalpellinae. The retention of a generalised sperm morphology in Catomerus is further consistent with the derivation, on other grounds, of the Balanomorpha from a scalpelloid ancestry. Within the Balanomorpha, sperm data offer indications of phylogenetic patterns in the Chthamaloidea (Chamaesipho derived from catophragmids independently of the chthamalids), Coronuloidea (Cylindrolepas related to Tubicinella; tetraclitids monophyletic and including Austrobalanus) and Balanoidea (archaeobalanids polyphyletic; Armatobalanus related to Pyrgomatidae; Balanus and the megabalanines both probably complex groups of perhaps multiple origins). Present sperm data do not assist in the elucidation of relationships between balanomorph superfamilies. Basal members of each superfamily retain a generalised thoracican sperm structure.

 
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Bibliographic Data

Short Form
Healy and Anderson, 1990, Rec. Aust. Mus. 42(1): 1–26
Author
J. M. Healy; D. T. Anderson
Year
1990
Title
Sperm ultrastructure in the Cirripedia and its phylogenetic significance
Serial Title
Records of the Australian Museum
Volume
42
Issue
1
Start Page
1
End Page
26
DOI
10.3853/j.0067-1975.42.1990.104
Language
English
Date Published
23 March 1990
Cover Date
23 March 1990
ISSN
0067-1975
CODEN
RAUMAJ
Publisher
The Australian Museum
Place Published
Sydney, Australia
Subjects
CRUSTACEA: OSTRACODA
Digitized
24 November 2008
Available Online
18 December 2008
Reference Number
104
EndNote
/Uploads/Journals/17722/104.enw
Title Page
/Uploads/Journals/17722/104.pdf
File size: 101kB
Complete Work
/Uploads/Journals/17722/104_complete.pdf
File size: 9874kB