Describer

Xu, Zhao, Sullivan, Tan, Sander & Ma 2012

Time

Cretaceous Late Campanian

Classification

Saurischia Theropoda Tetanurae Coelurosauria Troodontidae

Diet

Carnivore

Fossilsite

Wulansuhai Formation, Bayan Mandahu, North Canyon locality, Wulatgehouqi, Inner Mongolia, China

Info

Abstract

The partial troodontid hindlimb IVPP V 10597 was originally described as a juvenile Saurornithoides mongoliensis. The present study reconsiders the taxonomic placement of this interesting specimen, given the significant advances in understanding of the Troodontidae that have taken place since it was first described. Morphological comparisons and numerical phylogenetic analyses indicate that V 10597 is more closely related to the sympatric Linhevenator tani that to Saurornithoides mongoliensis, raising the possibility that V 10597 might be a juvenile L. tani. However, V 10597 differs significantly from other troodontids, including L. tani in numerous hindlimb features and particularly in the proportions of various hindlimb elements. These differences are likely to be taxonomic, and suggests that V 10597 represents a new troodontid. Furthermore, histiological analysis indicates that V 10597 is unlikely to be a juvenile of L. tani or any other large troodontid. Based on the available morphological and histological information, we propose the erection of a new taxon, Philovenator curriei gen. sp. nov., based on V 10597. This new find increases the known taxonomic diversity and morphological disparity of Late Cretaceous troodontids.

Etymology

The name honors Dr. Philip J. Currie for his contributions to the study of maniraptoran dinosaurs, including the initial description of IVPP V 10597. The genus name also recalls the combining from of the Greek (philein), to love, and the Latin venator, hunter, suggesting a lover of the hunt.

Holotype

IVPP V 10597, a nearly complete lef hindlimb, including the following elements: nearly complete femur, partial tibia, partial fibula, astragalus-calcaneum complex, distal tarsals III and IV, metatarsals I,II,III,IV and V, pedal phalanges I-1, II-1, II-2, II-3,III-1,III2,IV-1,IV-2,IV-3, IV-4, and IV-5.

Locality and horizon

Bayan Mandahu, North Canyon locality, Wulatgehouqi, Nei Mongol; Wulansuhai Formation, Campanian, Upper Cretaceous (Jerzykiewicz et al., 1983)

Diagnosis

A small troodontid that cab be distinguished from other memebers of the group by the presence of the following autamorphies: a prominent process on the medial side of the femoral shaft slightly proximal to the distal end, a sheet-like tibial cnemial cresyt that expands significantly anteriorly, astragalo-calcaneal hemicondyles that are deep anteroposteriorly and separated by e deep and narrow groove, a proportionally extremely long and slender tarsometatarsus (tarsometatarsus/femur length ratio 1.25, tarsometatarsus length/width ratio 22.0), anterposterior depth much greater than transverse width at the mid-shaft of the tarsometatarsus, and a prominent, elongate psoterior flange that extends along most of the length of metatarsal IV and is about equal in depth to the metatarsal shaft.