currently represented by several partially complete (but extensively crushed) specimens
from the Middle Eocene of Germany. Lambrecht (1928) first classified Palaeotis within
Gruiformes (in the Otididae, the family that includes the living bustards), but on the basis
of subsequently discovered partial specimens, Houde and Haubold (1987) suggested a
placement within the Palaeognathae—a ‘primitive ratite’ within the Struthionidae
(ostriches). Evidence for this position included, amongst other characters, lack of the
closure of the ilioischiadic foramen (character 24 of Lee et al. 1997; hypothesized to be
derived within ratites, as noted by Houde and Haubold 1987). This more primitive
position for Palaeotis within the ratites was rejected by Peters (1988) who considered that
this bird should be classified close to the extant rheas (Rheidae) (Figure 12.4).
By use of the character descriptions presented by Lee et al. (1997), the known
specimens of Lithornis from the London Clay Formation were coded (Appendix 12.1) and
a phylogenetic analysis was run with the same additional terminals as Lee et al. (1997).
Although a large number of specimens from the London Clay were referred to Lithornis by
Houde (1988), only those that consist of more than one element in certain association
were included within this analysis (Appendix 12.1). In addition to Lithornis, specimens of
Palaeotis weigelti were also included in the analysis. Codings for this taxon are based on
fossil material examined in the Senckenberg Museum, Frankfurt (SMF-ME 1578: a
compressed slab comprising a complete articulated individual that was referred to
Palaeotis weigelti by Peters 1988), and a cast of GM 4362 (a partially complete, but
crushed, individual) referred and described by Houde and Haubold (1987). Parsimony
analysis of the complete dataset (Appendix 12.1), including a composite ‘London Clay
Lithornis’ and Palaeotis, resulted in the production of a single MPT (91 steps; CI: 0.758;
RI: 0.794). In this tree (Figure 12.4), Lithornis is hypothesized to be the sister taxon to the
monophyletic ratites. Within this latter grouping, Palaeotis is recovered as the sister taxon
to two clades, Casuarius plus Dromaius, and Struthio plus Rhea (Figure 12.4). Interestingly,
inclusion of the fossil taxa effects no changes to the topology for extant taxa proposed by
Lee et al. (1997, figure 7.2).
The position of the composite London Clay Lithornis in a more derived position than
tinamous, and as the sister taxon to the other included taxa, is supported in this analysis
on the basis of the following derived character-states (numbered as listed by Lee et al.
1997, their appendix 1, and as preserved in the specimens considered): 8 (scapula and
coracoid fused; seen in BMNH PAL A 5303 and A 5425); 12 (internal tuberosity of
humerus knoblike, having a degree of medial protrusion; seen in BMNH PAL A 5204,
BMNH PAL A 5303, BMNH PAL A 33138, BMNH PAL A 38934, BMNH PAL A 5425);
13 (deltoid crest raised from the base of the external tuberosity; seen in BMNH PAL A
5204, BMNH PAL A 5303); 18 (pronounced external epicondyle of humerus; seen in
BMNH PAL A 5425). Characters that are not preserved in the available London Clay
specimens, but that are hypothesized to support the monophyly of this grouping are: 2
(absence of posterior lateral processes on the sternum); 11 (humerus longer than the
ulna); 17 (transverse ligamental sulcus shallow; reversed in the moa Dinornis); 25
(transverse processes of sacral vertebrae broad and fused); 26 (puboischial bar present);
35 (supratendinal bridge of tibiotarsus absent); 41 (posterior margin of external condyle of
tibiotarsus extended laterally).
BASAL RADIATIONS WITHIN THE NEORNITHES 275