103. Jamieson, B.G.M. 1990a. The ultrastructure of the spermatozoa of Petalomera lateralis (Gray) (Crustacea, Brachyura, Dromiacea) and its phylogenetic significance. Invertebrate Reproduction and Development 17, 39-45.
The dromiid sperm, as exemplified by Petalomera lateralis and Dromidia
  antillensis, differs markedly from spermatozoa of other crabs (the
  Oxystomata-Oxyrhyncha-Cancridea-Brachygnatha assemblage) in the discoid,
  relatively undifferentiated acrosome capping and not embedded in the
  nucleus (plesiomorphies); the capitate form of the perforatorium and the
  composition of this (autapomorphies); the greater, apomorphic, reduction
  of cytoplasm and organelles, including mitochondria and centrioles; and
  the absence (Petalomera) or brevity (Dromidia) of nuclear arms. In view of
  some similarities of the acrosome to those of Eubrachyura suggestive of
  relationship, brevity of arms may be secondary by reduction. Presence of
  well developed nuclear arms is a synapomorphy of all investigated non
  -dromiid brachyurans and of the Palinura, Astacidea and Anomura while
  absence is a symplesiomorphy of other Malacostraca. If brevity of arms in
  dromiids were plesiomorphic, the Dromiacea might be derived from early
  decapods before evolution of the Palinura-Astacidea-Anomura-Brachyura
  assemblage as suggested by their non-brachyuran, anomuran type larvae. If
  dromiids are monophyletic with true crabs, zoeal morphology would demand a
  basal position in the Brachyura. Exclusion of Raninoidea from the
  Dromiacea, or from a podotreme group consisting of the Dromiacea
  -Archaeobrachyura, is advocated in view of clear synapomorphies of
  raninoid sperm with those of the Oxystomata-Oxyrhyncha-Cancridea
  -Brachygnatha assemblage (e.g. spherical, embedded, more complexly zoned
  acrosome) which are not seen in dromiids.