Pinpanetta vickersrichae

Worthy, Trevor H., 2009, Descriptions and phylogenetic relationships of two new genera and four new species of Oligo-Miocene waterfowl (Aves: Anatidae) from Australia, Zoological Journal of the Linnean Society 156 (2), pp. 411-454 : 422-423

SPECIES PINPANETTA VICKERSRICHAE

SP. NOV. ( FIGS 1 , 3 )

Holotype: SAM P.42703, R humerus in two parts ( FIG. 1C, 1D, 1H, 1I ), missing small part midsection of shaft, dorsal part deltoid crest, and tip of ventral tubercle. Bone pale with areas of orange staining.

Diagnosis: A species of Pinpanetta which differs from Pi. tedfordi in humeral characters as follows: larger (12–20% broader); deltoid crest shorter with 43–45% of length extending distad of bicipital crest; dorsal pneumotricipital fossa deeper, not excavated under head; capital shaft ridge more compressed; attachment scar of supraspinatus more prominent; shaft does not narrow significantly distally; and facet for attachment of anterior ligament directed distally and slightly dorsally (not distoventrally).

Etymology: For Patricia Vickers-Rich in recognition of the substantial contribution she has made to the knowledge of Australian palaeornithology.

Type locality: Kanunka Microsite, Lake Kanunka, Lake Eyre Basin, SA, collection code VSQ 1978-127; collected by Museum Victoria, South Australian Museum , Queensland Museum field party July 1978 .

Horizon: Stratigraphy/Age: Etadunna Formation,?Ngapakaldi LF, Late Oligocene 24–26 Mya.

Distribution: Late Oligocene (24–26 Mya): Lake Eyre Basin, Callabonna Sub-basin, Namba Formation, Pinpa LF (Lake Pinpa and Billeroo Creek), Yanda LF (Lake Yanda); Tirari Subbasin, Etadunna Formation, Ngama LF (Mammalon Hill, Lake Palankarinna),?Ngapakaldi LF (Kanunka Microsite, Lake Kanunka).

Measurements of holotype: PW = 15.7 mm, length of deltoid crest = 20.7 mm, length head from dorsal tubercle = 11.8 mm, SW = 4.7, shaft depth = 4.1 mm, maximum DW = 11.3 mm, depth dorsal condyle = 6.6 mm.

Paratypes: Billeroo Creek , Well’s Bog Site , near Lake Pinpa : SAM P.41321, a fragmented R humerus reassembled into distal and proximal parts, lacking the bicipital crest and ventral pneumotricipital fossa ventrad of the capital groove, collected by T. R. Rich et al., 22 June 1978, collection code VSQ 1978-3, CUR- NAMONA (prov. ed.) sheet grid coordinates 319151, 31° 06 ′ S 140° 14 ′ E, Namba Formation, Pinpa LF. Tom Rich’s field notes for 22 June 1978 have the following entry: ‘In the afternoon, visited Wells Bog Site on Billeroo Creek. Here collected a bird humerus in several fragments plus the distal end of a tibiotarsus. This was out of the Namba Fm presumably. In addition we collected a Sthenurus claw from the Eurinilla Fm. as well as a lot of other Pleistocene material. This material was given the lot number VSQ 1978-3.’ Aaron Camens and THW relocated this area in June 2007 finding Namba Formation exposed on the North side of Billeroo Creek with adjacent Pleistocene outcrops at 31° 06.205 ′ S, 140° 13.912 ′ E, so locating this site c. 1 km south-east of where previously recorded .

Lake Pinpa, Namba Formation: SAM P.43127 (formerly AMNH 10724 ), worn dL humerus, collection code QMAM 264 , Site C, Pinpa LF ; SAM P.43136 (formerly AMNH 11408 ), dR humerus, north-west side lake, near CURNAMONA (prov. ed.) sheet grid coordinates 317148 ( R. H. Tedford, pers. comm. 30 Aug 2006), collection code QMAM 47 , preserved length = 31.7 mm. The shaft of AMNH 11408 is stained dark grey and is infilled with red sand suggesting it was derived from the Ericmas LF .

Description and comparison: In addition to the diagnostic characters above, Pi. vickersrichae differs from Pi. tedfordi further as follows: ventral pneumotricipital fossa extends as a deeper pocket under capital groove; pit for attachment of pronator brevis is located closer to centre on the ventral facies, rather than more cranially. The orientation of the facet for the anterior ligament is related to habit with specialist diving taxa having it directed somewhat ventrally, e.g. Oxyura and Mergus . That Pi. vickersrichae could be a less specialized diver than Pi. tedfordi is also indicated by the humeral shaft not narrowing distally as seen for example in Mergus and Oxyura ; however, the genera Nomonyx , Stictonetta, Biziura , Malacorhynchus , and Mionetta all lack distally narrow humeral shafts and Biziura is a good diver. In Pi. vickersrichae , the brachial fossa is well marked, aligned up the shaft, occupies about half shaft width, slightly less than in Pi. tedfordi , and is deepest distoventrally and separated from the ventral facies by a narrow ridge. Pinpanetta vickersrichae has a distinct dorsal ectepicondylar prominence of similar relative size to that in Pi. tedfordi and Malacorhynchus .

Measurements: See Table 2.

Figures

Figure 1. Right humeri of Pinpanetta species, A–E, cranial view, and F–J, caudal view. A, F, Pinpanetta tedfordi SAM P.41257, holotype; B, G, Pi. tedfordi UCMP 56998, paratype; C, D, H, I, Pi. vickersrichae SAM P.42703, holotype two nonarticulating fragments of one bone; and E, J, Pi. fromensis SAM P.43128, holotype. Scale bars = 10 mm. See main text for abbreviations.

Figure 3. Referred elements of Pinpanetta vickersrichae: A, left coracoid MV P.222418 in dorsal aspect; proximal left carpometacarpus AMNH 10770 in: B, ventral; C, caudal; and D, dorsal aspects; E, distal right tibiotarsus SAM P.24529, in anterior aspect. Scale bars = 10 mm. See main text for abbreviations.