Nestor undetermined

Wood, Jamie R., Mitchell, Kieren J., Scofield, R. Paul, Tennyson, Alan. J. D., Fidler, Andrew E., Wilmshurst, Janet M., Llamas, Bastien & Cooper, Alan, 2014, An extinct nestorid parrot (Aves, Psittaciformes, Nestoridae) from the Chatham Islands, New Zealand, Zoological Journal of the Linnean Society (Zool. J. Linn. Soc.) 172 (1), pp. 185-199 : 191-195

NESTOR CHATHAMENSIS WOOD, MITCHELL, SCOFIELD & TENNYSON SP. NOV.

Holotype: CM Av 21348 ( Fig. 7 ), premaxilla, collected by M. Pohio in July 1967.

Measurements of holotype: Length, 50.6 mm; proximal width, 19.9 mm; depth, 15.5 mm.

Type locality: Rocky Hill, Petre Bay, Chatham Island.

Etymology: After the Chatham Islands, New Zealand, ( Fig. 1) where N. chathamensis formerly occurred.

Diagnosis: A species of Nestor that was significantly larger than N. productus and differing from N. notabilis and N. meridionalis in the following skeletal features and allometries:

1. Mandible: the mandible of N. notabilis is distinct from both those of N. meridionalis and N. chathamensis in that the down-curvature of the ventral surface begins significantly forward of the fenestra rostralis mandibulae ( Fig. 3 ). In both N. meridionalis and N. chathamensis the downcurvature begins nearly adjacent to the fenestra rostralis mandibulae; however, the ranges of maximum mandible depths for these two species do not overlap (11.7–13.8 mm in N. chathamensis , N = 12; and 13.9– 17.3 mm in N. meridionalis , N = 7) [NB: Holdaway & Worthy (1993) noted a minimum mandible depth in kaka of 12.58 mm; however, we are unsure whether the measurement was taken in a comparable way to ours, or which specimen this was from].

2. Premaxilla: the ratio of premaxilla length to depth in N. chathamensis is intermediate between the ratios for N. notabilis and N. meridionalis (ranges from 3.3– 3.7 in N. notabilis ; 2.9–3.3 in N. chathamensis ; and 2.5–2.9 in N. meridionalis ). In a plot of premaxilla length vs. depth, we found no overlap amongst the hulls of the three species ( Fig. 2 ).

Dist., distal; Prox., proximal; Stern., sternal.

3. Ratio of humeral: femoral length: the femur is longer relative to the humerus in N. chathamensis than N. notabilis and N. meridionalis ( Fig. 8A ). As no associated femoral and humeral elements attributable to individual N. chathamensis were identified, the ratio of humeral: femoral length was calculat- ed using mean bone lengths, and was 1.08 for N. chathamensis , compared with mean ratios of 1.18 ± 0.03 for N. notabilis and 1.19 ± 0.02 for N. meridionalis ( Fig. 8A ).

4. Pelvis proportions: the pelvis of N. chathamensis ( Fig. 3 ) is broad, having a significantly smaller length to width ratio than those of N. meridionalis ( Fig. 8B ), as well as most N. notabilis pelves. At the extreme, N. notabilis pelves can exhibit the same length to width ratio as in N. chathamensis ( Fig. 8B ), but are larger in size, with no specimens examined being as small as the N. chathamensis pelvis ( Table 1).

Nestor chathamensis was significantly larger than N. productus in all elements examined (except the radius length, which, as discussed above, may have been overestimated for N. productus ; Table 1), but insufficient skeletal material of the latter was available to permit a detailed comparison of the two taxa.

Paratypes: Cranium : CM Av 6328, Chatham Islands, collected by J. J. Fougere, purchased by Canterbury Museum on 27.iii.1919 . Mandible : CM Av 6332, Chatham Islands, collected by J. J. Fougere, purchased by Canterbury Museum on 27.iii.1919 . Humerus: left, CM Av 27412, Maunganui dunes, Chatham Island , collect- ed by R. J. Scarlett, J. Anton, B. Campbell, D. Crockett, 22.i.1973 . Ulna: left, NMNZ, S.32922, Maunganui Beach, Chatham Island , collected by P. R. Millener, 20.i.1993 . Radius: right, CM Av 31813, Long Beach dunes, south of Henga, Chatham Island , collected by R. J. Scarlett, 18.xii.1972 . Carpometacarpus : right, CM Av 31650, Long Beach dunes, north of Henga, Chatham Island, collected by W. Campbell, 23.xii.1972 . Pelvis: NMNZ S.29990 ( Millener, 1999: fig. 10), site #127/91, Long Beach, Chatham Island , collected by P. R. Millener, 2.iii.1991 . Femora: right, CM Av 30136, Maunganui dunes, Chatham Island , collected by R. J. Scarlett, J. Anton, B. Campbell, D. Crockett, 22.i.1973 ; right, CM Av 21348, Rocky Hill, Petre Bay, Chatham Island , collected by M. Pohio in vii.1967 . CM Av 21348 is the specimen from which DNA was obtained in this study. Note also that the registration number is assigned to the collection rather than the specimen, and is shared by the holotype. As there are no duplicate parrot elements in this collection it is likely that the bones may be from an individual bird. Tibiotarsus: left, NMNZ S.32583, Long Beach , Chatham Island , collected by P. R. Millener and N. H. Hyde, 17.ii.1992 . Tarsometatarsus: right, CM Av 27495, first dune blowout north of Henga, Long Beach, Chatham Island , collected by L. C. Edlin, 21.xii.1972 . Palatine: NMNZ S.24889, Cape Pattison to Maunganui, Chatham Island , collected by P. R. Millener, 8.i.1988 . Scapula: left, NMNZ S.29653, Long Beach, Chatham Island , collected by P. R. Millener, 22.ii.1991 . Proximal phalanx of digitus major: left, CM Av 30143, Maunganui, Chatham Island , collected by R. J. Scarlett, J. Anton, B. Campbell, D. Crockett, 22.i.1973 . Furcula : CM Av 7363, Chatham Islands, collected by J. J. Fougere, purchased by Canterbury Museum on 27.iii.1919 .

width. Palatine: 42.3 mm long. Scapula: 9.0 mm proximal width. Proximal phalanx of digitus major: 21.3 mm long. Furcula: 31.4 mm long, 24.1 mm maximum width.

Referred material: All late Quaternary nestorid parrot remains from the Chatham Island archipelago are referred to N. chathamensis . A list of N. chathamensis material from the collections of Te Papa and Canterbury Museum is presented in Table S3.

Distribution: Formerly of the Chatham Island archipelago, New Zealand. Nestor chathamensis bones have been recorded from late Quaternary deposits on Chatham ( Millener, 1999), Pitt (A. J. D. Tennyson & J. R. Wood, unpubl. data), and Mangere Islands ( Tennyson & Millener, 1994). It is likely however, given the dispersal ability of parrots and the forested habitats available, that the species was also present on the other islands in the group (e.g. Little Mangere and South East Islands).

Paratype measurements: Cranium: 48.4 × 37.4 mm. Mandible: 63.8 mm long. Humerus: 62.1 mm long, 5.4 mm minimum shaft width, 12.6 mm distal width, 19.3 mm proximal width. Ulna: 66.6 mm long. Radius: 62.3 mm long. Carpometacarpus: 42.6 mm long; 10.1 mm proximal width, 6.5 mm distal width. Pelvis: 43.8 mm long, 35.5 mm maximum width, 15.8 mm dorsoventral depth. Femora: 58.3–60.7 mm long, 5 mm minimum shaft width, 12.7–12.9 mm proximal width, 13.2– 13.5 mm distal width. Tibiotarsus: 84.1 mm long (81.5 mm minus cnemial crest), 9.3 mm distal width. Tarsometatarsus: 33.8 mm long, 4.2 mm minimum shaft width, 10 mm proximal width, 12.6 mm distal

Figures

Figure 2. Unimodal distribution of nestorid parrot humeri from the Chatham Islands.

Figure 3. Comparison of skeletal elements from New Zealand nestorid parrots: Nc, Chatham Islands parrot (Nestor chathamensis); Nm, kaka (Nestor meridionalis); Nn, kea (Nestor notabilis) including certain features discriminating kea and kaka (some originally described by Holdaway & Worthy, 1993). A, right tarsometatarsi in dorsal view, showing the extended shaft in N. notabilis; B, ramus of mandibles in left lateral view, showing the different positions of the edge of the fenestra rostralis mandibulae (dashed line) relative to the point of down-curvature on the lower surface (arrowed); C, premaxillae and crania in left lateral view, showing the extension of the processus paraoccipitalis past the processus lateralis parasphenoidalis (arrowed) in N. notabilis but not N. meridionalis or N. chathamensis, as indicated by the dashed lines, and the postorbital process (circled) that is rounded in N. notabilis but triangular in N. meridionalis and N. chathamensis; D, left humeri in caudal view, showing differences in angles between the shaft and bicipital crest (arrowed); E, right palatini in ventral view, showing relatively wide crista ventralis (circled) and straight crista lateralis (arrowed) in N. meridionalis and N. chathamensis; F, pelves in dorsal view; G, pelves in right lateral view. Scale bars = 10 mm.

Figure 7. Holotype of Nestor chathamensis (Canterbury Museum AV21348); premaxilla in A, dorsal; B, ventral; and C, right lateral views. Scale is in mm.

Figure 8. Ratios of (A) pelvis length: width, and (B) humerus: femur length in New Zealand nestorid parrots. Note: as no associated skeletal remains are known from the Chatham parrot (Nestor chathamensis), the humerus: femur length ratio was calculated using mean lengths for each element.