Ganguroo robustiter, sp. nov. (Macropodoidea, Marsupialia), a middle to early late Miocene basal macropodid from Riversleigh World Heritage Area, Australia

ABSTRACT——Cranial and dental remains of the middle to early late Miocene macropodid kangaroo, Ganguroo robustiter, sp. nov., are described. Postcranial remains of G. robustiter were previously described as referable to G. bilamina. Ganguroo robustiter is more robust (approximately 20% larger) and more derived than G. bilamina and G. bites, in having a larger m4, a well-developed posterolingual ridge and lingual cingulum on P3, a longer P3/p3, and no stylar cusp C on M3–M4. We used previously published data matrices to analyze the phylogenetic relationship of G. robustiter. Both phylogenetic analyses, using craniodental and postcranial characters, place G. robustiter within Macropodidae, as the sister taxon to sthenurines and macropodines. Species of Ganguroo are not found to be monophyletic despite their extreme similarity in character scores. This may be due to the large amount of missing data for G. bilamina and G. bites for which no postcranial remains have been identified. Phylogenetic results are ambiguous, recovering unresolved trees with low bootstrap values, but the generic assignment of these taxa is maintained because they are remarkably similar. Species of Ganguroo may represent a phyletic lineage, with species increasing in size and losing cusp/cuspids on their premolars through time, which appears to coincide with a broader record of changing vegetation and climates through the middle Miocene.http://zoobank.org/urn:lsid:zoobank.org:pub:D0B542BE-C673-4260-8381-8B163A35AC36SUPPLEMENTAL DATA——Supplemental materials are available for this article for free at www.tandfonline.com/UJVP

摘要：本文记述了中新世中期至晚中新世早期的袋鼠科（Macropodidae）新种粗壮冈古罗袋鼠（Ganguroo robustiter, sp. nov.）的颅骨与牙齿遗骸。此前曾有研究将粗壮冈古罗袋鼠的肢骨遗骸归入双板冈古罗袋鼠（G. bilamina）。相较于双板冈古罗袋鼠与G. bites，粗壮冈古罗袋鼠体型更为粗壮（体型约大20%）且演化特化程度更高，具体表现为：下第四臼齿（m4）更大，上第三前臼齿（P3）发育有完善的舌后侧脊与舌侧齿带，上第三前臼齿/下第三前臼齿（P3/p3）更长，且上第三、第四臼齿（M3–M4）不具外齿尖C。本研究采用已发表的数据矩阵，对粗壮冈古罗袋鼠的系统发育关系进行分析。基于颅骨牙齿特征与肢骨特征开展的两项系统发育分析均显示，粗壮冈古罗袋鼠隶属于袋鼠科，且作为短面袋鼠亚科（Sthenurinae）与袋鼠亚科（Macropodinae）的姊妹群。尽管冈古罗袋鼠属各物种的性状得分极为相似，但该属并非单系群。这一现象可能源于双板冈古罗袋鼠与G. bites存在大量缺失数据，且二者尚未发现肢骨遗骸。系统发育分析结果存在歧义，得到的系统发育树分辨率较低且自举支持率偏低，但由于各分类单元间形态极为相似，仍保留其原有的属级归类。冈古罗袋鼠属各物种可能构成一个演化支系，随着时间推移，其体型逐渐增大，前臼齿的齿尖逐渐消失，这一演化趋势似乎与中新世中期更广范围的植被与气候变迁记录相吻合。http://zoobank.org/urn:lsid:zoobank.org:pub:D0B542BE-C673-4260-8381-8B163A35AC36
补充数据：本文的补充材料可通过www.tandfonline.com/UJVP免费获取。