Relicts from Tertiary Australasia: undescribed families and subfamilies of songbirds (Passeriformes) and their zoogeographic signal
Author
Schoddei, Richard
Author
Christidis, Les
text
Zootaxa
2014
2014-04-14
3786
5
501
522
journal article
5634
10.11646/zootaxa.3786.5.1
cdd39956-de72-43ea-afa3-cf79f805dd83
1175-5326
4913561
D2764982-F7D7-4922-BF3F-8314FE9FD869
Pachycare
and
Oreoscopus
New Guinean
Pachycare
was formerly placed in the corvoid family
Pachycephalidae
(Australasian whistlers), presumably because of bright yellow and grey plumage, form of bill, and “loud, melodious, whistled and explosive” vocalizations (
e.g
.
Mayr 1941
,
1967
;
Rand & Gilliard 1967
;
Sibley & Monroe 1990
;
Dickinson 2003
;
Boles 2007a
).
Coates (1990: 206)
nevertheless expressed reservations about an exclusively whistler-like voice. Mack & Opel (2006), corroborated by data in ANWC, also showed that
Pachycare
builds a domed nest near the ground and lays white, reddish-spotted eggs, characteristic of many acanthizids (
Acanthizidae
) but unlike any pachycephalid. It has a dusky subterminal tail band in the outer rectrices as well, a trait that appears repeatedly in one form or another throughout the
Acanthizidae
, but is otherwise absent in
Pachycephalidae
. The position of
Pachycare
in the meliphagoid
Acanthizidae
has since been established by
Norman
et al
. (2009a)
. Using 2644 base pairs of multi-locus nDNA and mtDNA sequence and osteological data, their study compared
Pachycare
with a comprehensive range of acanthizid genera including
Oreoscopus
, two genera of
Pachycephalidae
, and genera of three and five further meliphagoid and corvoid families respectively.
Pachycare
was recovered as sister to the northeast Australian Fernwren
Oreoscopus
in
Acanthizidae
, in a clade sister in turn to all other acanthizids. Support for pairing
Pachycare
and
Oreoscopus
was strong, and the node placing them sister to the rest of
Acanthizidae
was fully resolved. Similarly,
Gardner
et al
. (2010)
recovered
Oreoscopus
as sister to all other primary acanthizid lineages at some depth, although they did not examine
Pachycare
.
Distinctive osteological features of
Oreoscopus
―narrowly-winged ectethmoids, clavoid maxillo-palatines and completely perforate anterior synsacral foramina (
Schodde & Mason 1999: 134
)―also identify that genus as a deeply-diverged lineage in the
Acanthizidae
. Concerning the sister relationship between
Oreoscopus
and
Pachycare
, moreover, DNA divergence between them is almost as deep as between them and the rest of
Acanthizidae (
Norman
et al
. 2009a
)
. This divergence is matched by marked differences in form, behaviour and niche.
Oreoscopus
is a quiet, dun-colored, troglodyte-like litter-forager of the forest floor; and it has completely operculate nostrils adapted to its mode of foraging. In contrast,
Pachycare
is a noisy, active, and brilliantly yellow and grey gleaner of foliage in the forest canopy; and its skull structure, especially the temporal region, is markedly different (see subfamily diagnoses), indicating that
Pachycare
uses its bill in a different manner.
The combined DNA sequence and morphological data thus lead us to separate
Pachycare
and
Oreoscopus
in two monogeneric subfamilies of
Acanthizidae
. All other genera of
Acanthizidae
are circumscribed within the subfamily
Acanthizinae Bonaparte, 1854
.