Dear CRUST-Lers,
It is our pleasure to announce publication of a mongraphic work on the
Phosphatocopina from the Upper Cambrian of Sweden (Orsten):
Maas, A., Waloszek, D. & Müller, K.J. 2003. Morphology, ontogeny and
phylogeny of the Phosphatocopina (Crustacea) from the Upper Cambrian 'Orsten' of
Sweden. Fossils and Strata vol. 49, 1-238. Oslo.
This paper, with 45 plates and 74 text figures, includes the morphology and
ontogeny of Hesslandona unisulcata, other taxa in less detail, revises
the known phoshatocopine taxa and presents a phylogenetic analysis of the taxon
and Crustacea in general.
Phosphatocopina are interpreted by us as the sister group of Eucrustacea, based
on a set of synapomorphies such as the labrum, sternum with paragnath hims (of
mandibular sternite), mouth within atrium oris, furcal rami, and fine hairs on
all structures associated with feeding (labrum, sternum, setae of limbs). The
most significant apomorphy of this group N.N., which will be formally named in
due course (Siveter et al. in press), is however the presence of coxae on the
antenna 2 and mandible. All posterior limbs are "just" having a large
basipod and a smaller proximal setae-bearing endite medioproximally of it.
Another significant change from the stem level, as expressed in several other 'Orsten'
forms, is that there is a special armature on a enditic protrusions, a triplet
of anterior setae, a single spine or set of spines medially, and a posterior set
of setae. This triplet is retained plesiomorphically far into Recent descendent
groups, and by several photographs we can show that this set is even apparent on
the mandibular coxa, originating from the phylogenetically older proximal endite.
The anterior set are the "gnathobasic setae", occurring even/or still
in young Artemia, the median set develops into the marginal teeth of the
coxal blade, while the posterior set (fig. 66 in our monograph) is lost in the
Eucrustacea.
Phosphatocopina have not only these features in common with Eucrustacea and
plesiomorphies retained from earlier levels, such as the 4-legged early larva or
the serial postmandibular limbs with proximal endites, but have various
autapomorphies which set them off from the stemlineage and the Eucrustacea, such
as the bivalved shield from the beginning, the tiny a1, the strange fusion of
coxa and basipod during ontogeny on a2 and md, the reduced trunk, the low number
of only three endopodal segments on all postantennular appendages, and at least
6 segments included in a cephalothorax. Therefore, they can be easily
distinguished from all other bivalved arthropods, such as Bradoriida or
Ostracoda.
Lastly, a word to the Eucrustacea and their features, which we assembled too:
the special mouthpart 'maxillula', while the maxilla remains to be a trunk limb
for longer, and the nauplius (orthonauplius). The a2/mx2 excretory organs appear
here but may be an older feature. The eucrustacean nauplius and the
phosphatocopine larva are very special larvae because they use all structural
details developed in the common stem species of Phosphatocopina and Eucrustacea:
It has a coxa on a2 and md, paragnaths and fine hairs. Yet the 3-legged nauplius
does not bypass the morphology of 4-legged stem larvae when moulting to
more-legged stages. The naupliar head set is, accordingly, not a
phylogenetically old type of larva, but advanced, reducing the number of
segments compared to the phosphatocopine larva, while using the "latest
inventions" for feeding and locomotion. The larva of Phosphatocopina also
has coxae on a2 and md, but its functional fourth head limbs sets
Phosphatocopina clearly off from Eucrustacea in having retained the older "euarthropod
head larva".
Regrettably we will be unable to send out "reprints" which cost as
much as 55$, but may be the one or other is interested to obtain a copy from
Taylor & Francis, the company who now publishes this monograph series:
contact address is:
Taylor & Francis AS
Attn: Sandra Osorio
PO Box 2562 Solli
NO-0202 Oslo, Norway
FAX: +47-22129890
email: sandra.osorio@tandf.no
Please quote ref. SFOS03
Dieter Waloszek