Eomurruna yurrgensis

Hamley, Tim, Cisneros, Juan C. & Damiani, Ross, 2021, A procolophonid reptile from the Lower Triassic of Australia, Zoological Journal of the Linnean Society 192 : -

EOMURRUNA YURRGENSIS

( FIGS 3–24)

LSID: urn:lsid:zoobank.org:act:4FA81673-0CE1-4BA3-8329-B30EF45CC548 .

Etymology: The generic name is a combination of the Ancient Greek ἠώς, eos, dawn, and murruna, the name of the extant shingleback skink in the Bidyara language of Queensland. The shingleback skink is a stocky lizard that resembles a procolophonid both in its dentition and its overall appearance. The specific name is derived from the Bidyara yurrga, a hole in the ground, and the Latin suffix ensis, meaning ‘of’ or ‘belonging to’ (a place), which is a reference to The Crater, the locality near Bluff in Queensland, Australia, where most of the specimens were collected.

Holotype: QMF 18335 ( Figs 3, 5A–D, 6, 14, 15, 18–22). An articulated skeleton, missing most of the right limbs and the tail, collected by Ruth Lane in 1985.

Locality and horizon: ‘ Duckworth Creek’ ( QML 215 ), Colorado Station , south of Bluff , Queensland, Australia ( Fig. 1). Arcadia Formation , Rewan Group , Bowen Basin, Lower Triassic ( Warren et al., 2006) .

Diagnosis: Small procolophonid (skull length not exceeding 35 mm) distinguished from all other procolophonids by the following autapomorphies: (1) six to eight blunted, monocuspid maxillary teeth, circular in basal cross-section (mesiodistal length equivalent to labiolingual length), with broad bases (up to 86% of basal-apical length) but sharp apexes; (2) lateral surface of the maxilla bearing shallow, sinuous rugosities; (3) basicranium featuring a robust, pyramidal, alar process, rising from the clinoid process, forming the posterolateral border of the sella turcica; (4) presence of a vertical, inferior process, posterior to the alar process, in the prootic; (5) shallow, midconical tubercle located between the dorsum sellae and the anterior margin of the basioccipital; (6) canalis semicircularis anterior of the prootic not reaching the external surface of the bone; (7) bilobate end of the ventral ramus of the opisthotic, lobes being separated by a deep sulcus; (8) humerus bearing a prominent tuberosity, anterior to the long axis of the bone, on its proximal articular surface; (9) femur sigmoidal, curving dorsally proximally and ventrally distally.

Referred specimens: QMF 6677 cranium; QMF 6678 fragmentary maxilla; QMF 6679–6683 crania; QMF 6684 maxilla and lower jaw; QMF 6685 isolated teeth; QMF 6686 maxilla; QMF 6687 scapular girdle; QMF 6688 cranium; QMF 6689 left maxilla and lower jaw; QMF 6690 cranium; QMF 6691 maxilla and lower jaw; QMF 6692 three vertebrae; QMF 6693–6694 crania; QMF 6695 left maxilla and lower jaw; QMF 6696 maxillary fragments; QMF 6697 cranium and long bones; QMF 6698 vertebrae; QMF 6699 probable pelvic girdle and vertebrae; QMF 6700 cranium and mandible; QMF 6701 interclavicle and clavicle; QMF 6702 cranium; QMF 6703 maxilla and lower jaw; QMF 6704 complete cranium; QMF 6705–6709 crania; QMF 6714–6718 vertebrae; QMF 17995 partial maxilla and lower jaw; QMF 49497 cranium, vertebrae, partial scapular girdle and humerus; QMF 49501 partial cranium, basicranium, scapular girdle, humerii and manus; QMF 49502 interclavicle; QMF 49504 scapular girdle; QMF 49507–49508 crania; QMF 49510 cranium and partial postcranium; QMF 49511 cranium; QMF 49512 almost complete cranium; QMF 49513 lower teeth; QMF 49514 right femur; QMF 49516 well preserved cranium; QMF 49517–49519 crania. All referred specimens collected at ‘The Crater’ (QML 78), Rewan Station, south-west of Rolleston, Queensland, Australia, Arcadia Formation, Rewan Group, Bowen Basin, Lower Triassic ( Warren et al., 2006).

Collectors: QMF 6677–6718 , Alan Bartholomai; QMF 49497 and QMF 49510 , Natalie Schroeder; QMF 17995, 49512 and 49519, Anne Warren; QMF 49501 , Ben Thulborn and Angus Hamley ; QMF 49508 , Terri Colville; QMF 49511 , Ross Damiani.

DESCRIPTION OF THE CRANIAL SKELETON