Tympanocryptis petersi MELVILLE, CHAPLIN, HIPSLEY, SARRE, SUMNER & HUTCHINSON, 2019
Can you confirm these amateur observations of Tympanocryptis petersi?
|Higher Taxa||Agamidae (Amphibolurinae), Sauria, Iguania, Squamata (lizards)|
|Common Names||E: Lined Earless Dragon|
|Synonym||Tympanocryptis petersi MELVILLE, CHAPLIN, HIPSLEY, SARRE, SUMNER & HUTCHINSON 2019|
|Distribution||Australia (South Australia)|
Type locality: ‘Buchfelde’, near Gawler, South Australia
[approximately 34°35’, 138°31’ S],
|Types||Holotype. ZMB 54549 (formerly 4714, part), subadult male. Collector Richard Schomburgk, 1863. Specimen from the syntype series of T. lineata .|
Paratypes. ZMB 7414, same data as holotype, adult female. NMV D53031, Big Desert, 2.75 km NNW of Chinaman Well, Victoria, 35°51’2400 S, 141°39’1000 S, adult female; D57507, 14 km W of Hattah, Victoria, 34°46’ S, 142°06’ E, immature male; D59670, 14 km W of Hattah, Victoria, 34°46’ S, 142°06’ E, adult male; D74164, Lake Tyrell, Victoria, 35°20’ S, 142°50’ E, adult female; D74168, Lake Tyrell, Victoria, 35°20’ S, 142°50’E, adult male; SAMA R31159, ruins at Thompsons Beach Road, South Australia, 34°29’S, 138°19’E, adult male; SAMA R42648, Ngaut Ngaut Conservation Park, South Australia, 34°42’S, 139°370 E, subadult male; R53024, Deep Swamp, 5.1 km WSW of Alaman H/S, South Australia, 36°44’3500 S, 140°16’2500 E, adult male; R54592, 8 km N of Blanchetown, South Australia, 34°1500 S, 139°3600E, adult female; R58429, 6.6km ENE Tungketta Hill, Eyre Peninsula, South Australia, 33°43’1600 S, 135°7’3700 E, adult female; R58576, 5.1 km SSE Horne Lookout, Eyre Peninsula, South Australia, 33°43’4100 S, 135°21’4900 E, adult male; R61557 4.6 km NE Walkers Rock, Eyre Peninsula, South Australia, 33°31’2300 S, 134°53’1400 E, adult male.
|Diagnosis||Diagnosis. A species of Tympanocryptis with rostral scale continuous, or almost so, with the canthus rostralis, nasal scale below the canthus and not bordered below by enlarged scales, well-developed lateral neck fold, keeled dorsal head scales, usually a well-developed five-lined colour pattern in which the dorsolateral lines are equal to or broader than the vertebral line, no lateral skin fold, venter variable— immaculate to weakly to moderate brown flecks on throat (Melville et al. 2019).|
Description. Lateral neck fold well developed, from angle of jaw to gular fold; spines along extent of fold. Head shape, moderately wide skull with moderately short snout. Head and snout with strongly keeled dorsal scales; keels irregular, those on the lateral scales aligned more obliquely than those on the more medial scales. Snout shape smoothly tapering in profile, the canthal scales continuous with the rostral scale. Nasal scale dorsal margin does not cross to the dorsal side of the canthus rostralis. No row of enlarged scales along the ventral margin of the nasal scale between the nasal and small snout scales. Dorsal body scales moderately to strongly keeled and imbricate. Numerous scattered enlarged spinous dorsal scales, at least twice the width of adjacent body scales, each with a strong median keel ending in a prominent spine directed posterodorsally, trailing edge of scale strongly raised. Enlarged spinous scales appear larger and more densely packed in the dark dorsal cross-bands than the paler interspaces, not arranged in longitudinal series. Ventral body scales smooth to weakly keeled, throat scales smooth to very weakly keeled. Thigh scalation heterogeneous, with scattered enlarged spinous scales similar to those on body. Lateral fold between axilla and groin absent. SVL to 59 mm in females and 54 mm in males.
Dorsal colour pattern variable in the degree of development and colour hue, from reddish brown to grey-brown with five dark brown transverse bands and with five-lined pattern variable, often well defined and continuous but often interrupted and expressed only where it crosses the dark cross- bands. Dorsolateral lines as wide as or wider than the vertebral line, well defined, straight edged, not expanding around the vertebral blotches. Vertebral and dorsolateral stripes continue weakly onto the tail. Pale supra-ocular bar usually strongly contrasting. Venter white, sometimes with weak to extensive dark peppering on the throat and, less commonly, the belly (Melville et al. 2019).
Comparison with other species. Tympanocryptis petersi overlaps or potentially contacts a number of other Tympanocryptis species.
At its eastern limits, T. petersi is within 200 km of T. pinguicolla. The two differ in the absence of a lateral skin fold in T. petersi (present in T. pinguicolla), variable presence of weakly keeled ventrals (always smooth in T. pinguicolla) and consistent pattern of five dark transverse body bands (frequently six or seven in T. pinguicolla). Tympanocryptis pinguicolla occurs in higher rainfall grassland habitats, in contrast with the preference of eastern T. petersi for semi-arid salt lake and mallee habitats. Tympanocryptis houstoni approaches (but does not contact) T. petersi to the west, differing in its pale vertebral light line clearly broader than the dorsolateral light lines, consistent presence of moderate to heavy black ventral speckling and sporadic presence of six or seven dark dorsal cross-bands.
Tympanocryptis petersi and T. argillosa sp. nov. (Species B) approach each other in the area between Lake Frome and on the eastern border of South Australia. Sampling from this area is very sparse, but there again seem to be some mismatches of morphological and molecular markers indicating a level of contact and at least occasional hybridization. Two specimens that are phenotypically T. argillosa sp. nov. (SAMA R46040, R48353) have T. petersi mtDNA, indicating past hybridization events; both specimens are from populations hundreds of kilometres north of the nearest morphotypical T. petersi. Unlike the case with T. tolleyi sp. nov. (Species D, see below), checking the identity of specimens with RAG1 produced inconsistent results, with one of the mitochondrially anomalous specimens (R48353) scoring as T. petersi, in agreement with the mitochondrial data but in conflict with the morphology. Similarly, another specimen (SAMA R54247) mitochondrially and morphologically typed as T. argillosa sp. nov. (Species B) was placed with T. petersi for RAG1. This specimen was included in the CT-scanned dataset and scores as an ‘extreme’ Species B with a particularly curved, deep snout. Overall, it is evident from the mitochondrial and nuclear DNA data that T. petersi and T. argillosa sp. nov. (Species B) are very recently diverged and there is evidence that some reticulate evolution occurred recently. Our recognition of the two as distinct species rests on a majority tendency of the DNA-typed specimens to accord with the morphology, notably snout shape and scalation, but this decision may need to be modified in future. At present, poor sampling in the putative overlap or contact zone roughly between Lake Frome and Lake Blanche prevents a more detailed inquiry into the nature and timing of genetic introgression between these two morphologically and biogeographically consistent entities.
Tympanocryptis petersi and specimens assigned to T. tolleyi sp. nov. (Species D) contact and narrowly overlap in the Gawler Ranges area of South Australia. All of the specimens from this area have T. petersi mtDNA, but most of the specimens in this region, running from Hiltaba in the west to Paney in the east, are unambiguously assignable to T. tolleyi sp. nov. (Species D) on morphology. Two of the morphologically problematic specimens were included in our limited RAG1 dataset, and both fell out with T. tolleyi sp. nov. (Species D). However, some males from a region running from Paney northwest to the area between Lake Acraman and the southern end of Lake Gairdner show a strongly developed vertebral light line and some females show better development of light dorsolateral lines over the dark cross-bands, both more like T. petersi than T. tolleyi sp. nov. (Species D). We believe this area represents a contact zone between the two, with some ongoing local gene flow in the eastern part of the Gawler Ranges (Melville et al. 2019).
|Comment||Distribution: see map in Melville et al. 2019: 6 (Fig. 1: species A)|
|Etymology||Named for Wilhelm Carl Hartwig Peters, pioneering German herpetologist and Director of the Zoological Museum of the University of Berlin from 1857 until his death in 1883. Peters coined the name Tympanocryptis and described its type species, T. lineata, based mainly on specimens from the Adelaide area.|