Jamieson, B.G.M. and Tudge, C.C.
1990b. Dorippids are
Heterotremata: evidence from ultrastructure of the spermatozoa of Neodorippe
astuta (Dorippidae) and Portunus pelagicus (Portunidae)
Brachyura: Decapoda. Marine Biology 106, 347-354.
Ultrastructural comparison between the sperm
of the dorippid crab Neodorippe
astuta (Fabricius, 1793) and the
portunid
Portunus pelagicus (Linnaeus, 1766) from
Queensland, Australia,
supports
placement of dorippids with portunids and their relatives in the
heterotreme
section of the Eubrachyura (the Heterotremata - Thoracotremata or the
Oxyrhyncha - Cancridea - Brachygnatha assemblage) and not with Ranina
ranina
(in the Archaeobrachyura or the Oxystomata). Similarities between
spermatozoa of N. astuta and of P.
pelagicus (and other
Eubrachyura) and R. ranina include:
the large
spherical,
multi-layered, capsule-bound acrosome vesicle; the electron-dense
operculum
capping the vesicle; an invaginated core, or perforatorium; concentric
zonation
of the contents of the vesicle; a layer of cytoplasm, between the
acrosome
vesicle and the nucleus, which contains mitochondria (mostly
degenerating) and
lattice-like lamellar complexes or membrane remnants; a diffuse nucleus
which
is bounded externally by a combined nuclear and plasma membrane and
cups the
scanty cytoplasm and the large acrosome vesicle; and lateral arms into
which
the chromatin extends. Characteristic eubrachyuran features of the N.
astuta
sperm absent from R. ranina are
the long perforatorium (short and
conical with
a unique subacrosomal chamber in R.
ranina) extending almost to the
operculum;
presence in the perforatorium of longitudinally arranged convulated
tubules; a
zone of acrosomal rays forming the
outer part of an inner dense zone; the presence of a thickened ring
surrounding
the basal part of the perforatorium; and, basally, two centrioles
(absent from
R. ranina but also from some
eubrachyurans). The sperm of N.
astuta is
more
similar to that of P. pelagicus
than to that of other investigated
Brachyura. A
heterotreme status of N. astuta
is thus unequivocally supported. Both
species
lack the posterior median process seen in the nucleus of majids and R.
ranina.