Mexico, and was described and named as a new
species (_Zenaidura yucatanensis_).

Salvadori (1893:373), Ridgway (1916:353) and Peters (1934:213-215)
agree that _Zenaidura yucatanensis_ Lawrence is a hybrid between
_Zenaidura macroura marginella_ and _Zenaida aurita yucatanensis_.
Ridgway (1916:355), however, notes that "... If _Zenaidura
yucatanensis_ Lawrence should prove to be really a distinct species,
and not a hybrid ... unquestionably _Zenaida_ and _Zenaidura_ can not
be separated generically, since the former is in every way exactly
intermediate between the two groups." In the event that the unique type
is a hybrid, the very fact of its existence supports the hypothesis
that the genera are more closely related than is currently recognized.

Serology

There have been no investigations having as their sole purpose the
clarification of the relationship of the genera _Zenaida_ and
_Zenaidura_. But some work has involved the comparison of the antigenic
content of individual columbids with the antigenic content of a member
of another species of the same family.

Irwin and Miller (1961) tested, along with other columbids, members of
_Zenaida_ and _Zenaidura_ for presence of, 1) species-specific antigens
of _Columba guinea_ (in relation to _Columba livia_) which are
designated A, B, C and E, and, 2) species-specific antigens of _C.
livia_ (in relation to _C. guinea_) which are designated A', B', C' and
E'.

In the first test all five species of _Zenaida_ and _Zenaidura_
possessed antigens A and C, and all but _auriculata_ possessed E. None
of the species gave evidence of the presence of the B antigen of _C.
guinea_ in their blood. In the latter test only _macroura_ had A', only
_asiatica_ had B' (_aurita_ was not tested for B'), and none had C' or
E'.

These results would indicate that the five species are similar
regarding antigenic content of the blood, and the variation is not
consistent within one or the other genus as presently known.

SUMMARY AND CONCLUSION

The avian genus _Zenaida_ is currently considered to be distinct from
the genus _Zenaidura_ by most columbid taxonomists. The jaw muscles of
six Mourning Doves (_Zenaidura_) and five White-winged Doves
(_Zenaida_) were investigated as to differences and similarities that
might clarify the relationships of the genera. The sizes and
proportions of skulls were also considered in 37 Mourning and
White-winged doves and two Eared Doves. Larger size of