Oedistomatinae

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 : 506-507

Subfamily Oedistomatinae , subfamilia nova ―plumed longbills

Type genus: Oedistoma Salvadori, 1876

Diagnosis. Small to very small plain creamy olive songbirds with long decurved bills, rounded wings, short plain tails, bare and lemon-colored periorbital rings, plumed flanks and discolorous yellowish-white pectoral tufts at the sides of the breast under the wings; sexes monomorphic except for smaller, shorter-tailed females; head slender with tight neck skin, the bill attenuated and decurved, evenly tapered throughout length, dark grey with whitish mandibular unguis, tomia microscopically dentate distally with fine, evenly spaced tuberculate teeth on both maxilla and mandible, narial depression elongate elliptic, with inoperculate, holorhinal and internally fully pervious nostrils opening externally in a long, meliphagid-like slit along ventral margin of narial depression, rictal bristles present, fine and sparse; corneous tongue a semi-closed canal extensively open at each end, with an extensively laciniate, meliphagid-like quadrifid tip in which the medial furcation is much deeper than the two lateral furcations, and their four lobes are laciniate only at the tips; skull with fully perforate interorbital septum except for narrow medial bar, swollen, broadly winged ectethmoids that reach the jugal bar, a fully aperturate palate with atrophied vomer and maxillo-palatines and slender palatines with narrow, raked shelf, and large, shallow and ill-defined temporal fossae flanked by short, ellipsoid postorbital processes projecting ventrally and long, spine-like zygomatic processes projecting anteriorly; sternum rectangular and moderately narrow, proportionally larger than in Toxorhamphus , with deep keel as deep as width of sternum, lateral trabeculae slender, c. ⅓–½ x length of sternum, hardly flared at tips, sternal rostrum short and deeply bilaterally compressed; wings moderately rounded, primaries 10 with p10 short and narrow, p7–p6 longest, and p8=p5; humeral fossae semidouble, with deep, trabeculated outer fossa and distinct, moderately deep tricipital fossa, the incisura capitis deep, ventral tubercle much protuberant, and pectoral crest short, not decurrent below fossae; tail short and squaretipped, tail/wing ratio c. (0.46–)0.47–0.52(–0.56), the rectrices 12, straight-sided with rounded tips; feet short, with stout toes and scutellate-laminiplantar tarsi, the scutes angled obliquely across the acrotarsus. Nest a small, deep closely woven hanging cup of plant fiber, lined with a loose felt of white plant down, camouflaged with a neat covering of small leaves bound in with cobweb, and slung from the rim in a horizontal fork; eggs c. 1 per clutch, ovoid, matt creamy white, sparsely sprinkled with fine specks of pale rust-red concentrated in a zone at the larger end around which are also scrawled several transverse lines of blackish-brown. Versatile, forest-living nectarivores and insectivores of forest midstages, probing and gleaning actively, nervously and acrobatically from forest lower to upper stages, flying swiftly and directly between sites and calling with repeated tweeting in flight; apparently monogamous.

Range and composition. Lowland to lower montane rainforests of New Guinea; one genus: Oedistoma Salvadori, 1876 , of two species: Oedistoma pygmaeum Salvadori, 1876 and O. iliolophum ( Salvadori, 1876) .

Comment. We use the name Oedistomatinae for this subfamily on the presumption that O. iliolophum ( Salvadori, 1876) is the sister species of O. pygmaeum Salvadori, 1876 , type species of Oedistoma . All molecular analyses comparing “ Oedistoma ” with Toxorhamphus and other groups of songbirds to date [?] have employed O. iliolophum solely as its representative. That species was previously included in the honeyeater genus Melilestes or tube-tongued longbill genus Toxorhamphus until Salomonsen (1967) moved it to Oedistoma without explanation. No substantive justification for this move has yet been published. DNA sequence data (Christidis et al., unpublished) confirm that O. pygmaeum and O. iliolophum are indeed sister species relative to other members of the Melanocharitidae ; and morphology is consistent with this hypothesis. With respect to Toxorhamphus , Oedistoma iliolophum (n = 40) and O. pygmaeum (n = 4) share exclusively: olive-grey dorsa and pale grey ventra yellowing on bellies and crissa; yellowish white pectoral tufts at the side of the breast; plain-tipped tails; bare, yellowish periorbital rings (although those of O. pygmaeum have vestigial white feathering as in Toxorhamphus novaeguineae ); evenly tapered bills with whitish unguinal stripe on the mandible; and, significantly, fine even toothing on distal sectors of both maxillary and mandibular tomia, without microscopic tuberculate teeth or compound toothing on the maxilla as found in Toxorhamphus . In sum, O. iliolophum and O. pygmaeum differ in little else than size and more plumose flanks in O. iliolophum . Accordingly we treat them as congeneric.

Group name. The term “plumed longbill” expresses an obvious and easily identified family-group difference from the tube-tongued longbills, Toxorhamphinae .