Family †Peipiaosteidae
†Peipiaosteus-Jurassic, China
Figure 6.Reconstruction of †Peipiaosteusfrom Zhou (1992). See further comments and revised interpretations and drawings in Grande &
Bemis (1996).
potheses must be tested by outgroup comparisons
to other actinopterygians.
Selection of taxa for outgroup comparison
Figure 3 shows the relationships of living Polypteri-
dae, Acipenseriformes, Lepisosteidae, Amiidae,
and Teleostei as currently understood (Lauder &
Liem 1983). There is now widespread acceptance
that, among living fishes, Polypteridae is the sister
group of all other Actinopterygii (Goodrich 1928,
Patterson 1982) andthat sturgeons and paddlefish-
es together form the next extant group on thecla-
dogram. Teleostei includes more than 20000 living
species, whereas Polypteridae, Acipenseriformes,
Lepisosteidae and Amiidae together only contain
about 45 living species. Of these 45 living species, 27
are Acipenseriformes, and this order also shows the
largest total biogeographic range of any living clade
Table 3.Species and biogeographic ranges of †Peipaiosteidae
Liu & Zhou 1965 (also see Grande & Bemis 1996a).
†PeipaiosteusLiu & Zhou 1965
†P. paniLiu & Zhou 1965 Upper Jurassic/Lower Cretaceous
†P. fengningensisBai 1983 Upper Jurassic/Lower Cretaceous
†Stichopterus Reis 1910
†S. woodwardiReis 1910 Lower Cretaceous-Trans-Baikal
†S. popoviYakovlev 1986 Lower Cretaceous-Mongolia- China
- China
of non-teleostean actinopterygians. Because of
their diversity and phylogenetic position as a basal
group within Actinopterygii, Acipenseriformes is
essential for comparative studies within extant and
fossil Actinopterygii.
The earliest known complete skeletons of acti-
nopterygians are from the Devonian (see Long
1995), but isolated scales are reported from the Up-
per Silurian. By the Carboniferous their diversifica-
tion had produced a great variety of fishes, com-
monly known as ‘paleonisciforms’ (a grade, see
Gardiner 1993). ‘Typical’ Paleozoic and Mesozoic
paleonisciforms have heavy, rhombic scales armor-
ing the body, a heterocercal tail, a well ossified skull
with solid bony cheeks, and large eyes. More than
200 genera of paleonisciforms are known, but many
are poorly preserved or inadequately studied. In-
creasing knowledge of the anatomy of certain Pale-
ozoic genera such as †Cheirolepis(Pearson &West-
oll 1979, Pearson 1982), †Mimiaand †Moythomasia
(Gardiner 1984a) allows their placement with
greater certainty within the phylogenetic scheme
for recent actinopterygians, and we follow Gardin-
er & Schaeffer (1989) in placing these genera near
the base of Actinopterygii and including them as
outgroups in our analysis of Acipenseriformes.
Several living and fossil genera are relevant out-
groups for analyzing relationships among Acipen-
seriformes (Figure 4). Two Mesozoic genera often