Cinclosoma sp.
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publication ID |
https://doi.org/ 10.4202/app.00485.2018 |
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publication LSID |
lsid:zoobank.org:pub:C1904F94-7AF8-4069-8284-61A6EC59F4C1 |
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persistent identifier |
https://treatment.plazi.org/id/03888788-9D11-9666-7415-B0025C122785 |
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treatment provided by |
Felipe |
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scientific name |
Cinclosoma sp. |
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Fig. 2 View Fig .
Material.—QM F57969, proximal right tarsometatarsus with most of hypotarsus broken off, from Rick’s Sausage Site, Gag Plateau, Riversleigh World Heritage Area, Queensland, Australia. Based on biocorrelation of mammalian faunas, Rick’s Sausage Site is allocated to Riversleigh’s Faunal Zone C and is interpreted as middle Miocene in age ( Archer et al. 1989; Travouillon et al. 2011; Arena et al. 2015).
Measurements (in mm).—Preserved length 9.4; proximal width 5.1; cotyla medialis depth 3.5; cotyla lateralis depth 2.7.
Description.—QM F57969 ( Fig. 2A View Fig ) is referred to Cinclosoma because the tarsometatarsus exhibits the following combination of features: proximal tarsometatarsus stout; arcus extensorius short and approximately perpendicular to shaft long axis; lateral part of arcus extensorius situated well distally of dorsal margin of cotyla medialis; tuberositas m. tibialis cranialis small, centred in sulcus extensorius, and disto-laterally adjacent to arcus extensorius; medial shaft depth shallow. In extant species of Cinclosoma , the crista plantaris lateralis has a large, triangular peroneal foramen that is partially bound plantarly by a long hooked process on the proximal part of the crista plantaris lateralis ( Fig. 2B 2 View Fig ). In QM F57969 this process is broken off, but the proximal part of the crista plantaris lateralis is shallow and preserves the disto-dorsal edge of the foramen ( Fig. 2A 2 View Fig ), which indicates that the foramen was similarly large. Of these features, a small tuberositas m. tibialis cranialis that is situated centrally in the sulcus extensorius and disto-laterally adjacent to the arcus extensorius is considered an apomorphy of species of Cinclosoma .
The fossil tarsometatarsus additionally shares the following features with species of Cinclosoma : eminentia intercotylaris low; fossa on dorso-lateral side of eminentia intercotylaris shallow; fossa infracotylaris deep; foramina vascularia proximalia close together; plantar opening of medial foramen level with crista medialis hypotarsi; impressio lig. collateralis medialis low. Based on what is preserved of the medial, intermediate, and lateral crests of the hypotarsus, the hypotarsal canals for the flexor digitorum longus and flexor hallucis longus tendons are about equal in medio-lateral width, similar to extant species of Cinclosoma studied. The fossil tarsometatarsus differs from the corresponding bone of Ptilorrhoa species examined in being stouter and having less medio-lateral expansion of the cotylae; more elevated impressio lig. collateralis medialis; and a deeper fossa infracotylaris. It differs from species of Psophodes studied in being stouter; having a shorter arcus extensorius; and a relatively smaller tuberositas m. tibialis cranialis that is more circular and centred in the sulcus extensorius, rather than elongate and situated medially. Although specimens of Androphobus viridis were unavailable for study, the fossil can be distinguished from A. viridis in its much larger size ( Boles 2007).
QM F57969 differs from extant species of Cinclosoma studied in only a few features. Differs from all species of Cinclosoma studied in having a shallower sulcus ligamentosus. Differs from C. punctatum in having a more pronounced impressio lig. collateralis medialis. Differs from C. castanotum and C. castaneothorax in possessing a shallower groove for the tendon of M. fibularis longus. Differs from C. cinnamomeum in having a less developed protuberance on the proximo-medial corner of the cotyla medialis;
40 30 20 10 0 Ma Plio- Eocene Oligocene Miocene cene and a cotyla medialis larger than the cotyla lateralis, rather than being about equal in size. The fragmentary nature of the fossil and the many morphological similarities it shares with extant species of Cinclosoma preclude its allocation to a species with confidence.
Remarks.—QM F57969 corresponds to the larger end of the size range observed for tarsometatarsi of Cinclosoma punctatum (proximal width 5.1 mm in AM O.68471 and NMV B12872). The proximal tarsometatarsus width of C. cinnamomeum NMV B 8986 and NMV B12004 is 4.0 mm, which would be similar to or smaller than that expected for C. elachum sp. nov., based on size comparisons of the carpometacarpus and tarsometatarsus. Therefore, we can infer that QM F57969 represents a species that is considerably larger than C. elachum sp. nov.
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