(e.g. Unwin 1993; Hope 2002). However, the majority of this material is incompletely
preserved and so one of the oldest certain records for the order to date comes from the
Lower Eocene Green River Formation of the United States. This taxon, Gallinuloides
wyomingensis (Figure 12.6), was placed within the extinct family Gallinuloididae by Lucas
(1900), now also considered to contain a number of somewhat younger and incompletely
known taxa (Milne-Edwards 1867–1871; Tordoff and Macdonald 1957; Mayr 2000).
Another well-preserved and early fossil representative of these birds is the genus
Paraortygoides known from a number of specimens from the Lower Eocene London Clay
Formation of the UK, and from the Middle Eocene deposit of Messel, Germany
(Figure 12.6).
Recently, the first morphological phylogenetic analysis for Galliformes, scored at the
level of individual extant genera, was published (Dyke et al. 2003). Based on more than
100 osteological characters, it is now possible to investigate the relationships of a number
of the better preserved fossil representatives of the order within a phylogenetic context
(Figure 12.6). As can be seen from the cladogram in Figure 12.6, the basic relationships
of the extant taxa within the order can be summarized with the mound-building
megapodes (Megapodiidae) as the most basal taxon, the sister of the cracids (i.e.
currassows, guans; Cracidae) and the more familiar phasianoids (i.e. pheasants,
partridges, guineafowl; Phasianoidea). Within this latter grouping, a number of the
Figure 12.6 (A) Hypothesis for the phylogenetic positions of the Lower Eocene taxa Gallinuloides and
Paraortygoides—well-preserved fossil representatives of order Galliformes (see text for details and
sources); (B–E) fossil elements of Paraortygoides from the Lower Eocene of England; (F) type specimen
of Gallinuloides.
278 GARETH J.DYKE