Pachycare, Gould, 1876

Schoddei, Richard & Christidis, Les, 2014, Relicts from Tertiary Australasia: undescribed families and subfamilies of songbirds (Passeriformes) and their zoogeographic signal, Zootaxa 3786 (5), pp. 501-522 : 502-503

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 .