Herpetofaunal diversity changes with climate: evidence from the Quaternary of McEachern’s Deathtrap Cave, southeastern Australia

Figures & data

FIGURE 1. Location and stratigraphy of McEachern’s Deathtrap Cave. A, map showing the location of MDC and other key fossil sites discussed in this study. B, depth-age plot. Ages are given in calibrated thousands of years ago (cal ka). C, longitudinal cross-section of MDC (modified from Kos, 2001). D, stratigraphy and associated ages of MDC. Ages are given in thousands of years ago (ka).

FIGURE 4. Results of the correspondence analyses excluding Amphibolurinae using the number of identified specimens, NISP, A, and minimum number of individuals, MNI, B, as symmetric maps (rows and columns as principal coordinates). Points (rows) represent different taxa, and triangles (columns) represent different sedimentary beds. Sizes of the symbols correspond to relative frequencies, while the color intensity of the symbols is proportional to their absolute contribution to the planar display. Ages of the sedimentary beds are given in calibrated thousands of years ago (cal ka).

TABLE 1. Character matrix of the morphotypes identified in the deposit.

	T. nigrolutea	Liopholis sp. morph 1	Liopholis sp. morph 2	Eugongylinae indet. 1	Eugongylinae indet. 2	Eugongylinae indet. 3	Eugongylinae indet. 4	Eugongylinae indet. 5	Sphenomorphinae indet. 1	Sphenomorphinae indet. 2	Sphenomorphinae indet. 3	Sphenomorphinae indet. 4
Meckel’s groove open (1)/open but narrow (2)/closed with v-shaped splenial notch (3)/closed with u-shaped splenial notch (4)	3	3	3	4	4	4	3	3	1	1	2	1
Splenial notch reaches up to ventral of tooth position	4–5	4–5	6–7	4	5–6	5–6	3–4	5	?	?	?	?
Number of tooth positions	12	21	20–21	26–27	24–25	24–25	21	22	21–22	21	18	18
Dorsal margin of the coronoid process convex (1)/straight (2)/concave (3)	2	2	3	2	2	3	2	?	2	2	3	2?
Dorsal margin of the angular process convex (1)/straight (2)/concave (3)	1	3	2	1?	2	1	?	?	3	3	2/3	?
Anteriormost inflection between the coronoid process and angular process positioned higher (1)/midway (2)/lower than midway (3) of the dentary height	1	1	1/2	?	3	3	?	3?	2	2	1	1
The gap of the posteriormost mental foramen and the next is wider (1)/about the same (2)/narrower (3) than gaps between the other foramina	2	1	2	3	3	2	1	2	3	3	3	2
The angle formed by the intersection of the posterior margins of the dorsal and angular processes measures more (1)/about the same (2)/less (3) than 90°	2	2	2	3	3	3	3?	3?	2	2	3	?
The coronoid facet shows a distinct step (1)/does not show a distinct step (2)	2	2	2	1	2	2	1	2	2	2	2	2
Surangular process is present (1)/absent (2)	2	2	2	1	1	1	2	?	1	2?	2	?
Number of mental foramina	?	7	7	4	4-5	4	4	4	6	6	5	7
Inferior alveolar foramen (IAF) is positioned anterior (1)/midway (2)/posterior (3) of the midway point along the dentary	3	3	3	3	3	3	3	3	NA	NA	NA	NA

FIGURE 2. Different morphotypes of the Egerniinae and Eugongylinae subfamilies. Scale bars equal 2.5 mm. A, right maxilla of Tiliqua nigrolutea (NMV P254415) in medial view. B, left dentary of Liopholis sp. morph 1 (NMV P254587). C, right dentary of Liopholis sp. morph 2 (NMV P256193). D, right dentary of Eugongylinae indet. morph 1 (NMV P256348). E, left dentary of Eugongylinae indet. morph 2 (NMV P254639). F, right dentary of Eugongylinae indet. morph 3 (NMV P256359). G, right dentary of Eugongylinae indet. morph 4 (NMV P256336). H, left dentary of Eugongylinae indet. morph 5 (NMV P254379). B–H, lingual, labial and occlusal views (from top to bottom). Abbreviations: a, angle formed by the intersection of the posterior margins of the dorsal and angular processes; ami, anterior-most inflection between the coronoid process and the angular process; ap, angular process; cf, coronoid facet; cp, coronoid process; ds, dental sulcus; iaf, inferior alveolar foramen; mf, mental foramina; sn, splenial notch; sp, surangular process; sym, symphysis.

FIGURE 3. Different morphotypes of the Sphenomorphinae and Amphibolurinae subfamilies. Scale bars equal 2.5 mm. A, right dentary of Sphenomorphinae indet. morph 1 (NMV P 254385). B, right dentary of Sphenomorphinae indet. morph 2 (NMV P254452). C, right dentary of Sphenomorphinae indet. morph 3 (NMV P254381). D, left dentary of Sphenomorphinae indet. morph 4 (NMV P254491). E, left maxilla of Amphibolurinae indet. morph 1 (NMV P254682), medial (left) and lateral (right) aspects. A–D, lingual, labial and occlusal views (from top to bottom). Abbreviations: a, angle formed by the intersection of the posterior margins of the dorsal and angular processes; am, anterior margin of the maxilla; ami, anterior-most inflection between the coronoid process and the angular process; ap, angular process; at, acrodont teeth; cf, coronoid facet; cp, coronoid process; lmf, labial maxillary foramina; mg, Meckelian groove; mf, mental foramina; mp, maxillary process; nr, naris ridge; pt, pleurodont teeth; sp, surangular process; ss, subdental shelf.

TABLE 2. Abundances of taxa in the different sedimentary beds based on the minimum number of individuals (MNI) and number of identified specimens (NISP). Ages of the sedimentary beds are given in calibrated thousands of years ago (cal ka).

Sedimentary Bed	Bed 15	Bed 14	Bed 12	Bed 11	Bed 10	Bed 9 -5
Age (cal ka)	1.70+/-0.16		6.46+/-0.12		8.46+/-0.20	13.54+/-0.17
Anura
Anura indet.	31 [32]	7 [7]	47 [51]	24 [25]	11 [12]	2 [2]
Squamata
Amphibulorinae
Amphibulorinae indet.	2 [2]		1 [1]
Amphibulorinae morph 1	3 [3]
Scincidae
Scincidae indet.	41 [43]	27 [29]	63 [66]	46 [49]	23 [26]	10 [11]
Egerniinae
Egerniinae indet.	1 [1]	1 [1]	2 [2]	2 [2]		2 [2]
Tiliqua nigrolutea	1 [1]		1 [1]
Liopholis sp. morph 1	1 [1]	3 [3]	2 [3]		1 [2]
Liopholis sp. morph 2	3 [4]			2 [2]	1 [2]
Eugongylinae
Eugongylinae indet.	5 [5]	7 [7]	5 [5]	6 [6]	3 [3]	6 [6]
Eugongylinae morph 1	2 [2]		1 [1]
Eugongylinae morph 2	4 [4]	2 [2]	3 [3]	6 [8]	2 [2]
Eugongylinae morph 3	1 [1]	3 [3]	1 [2]	5 [5]	3 [3]	1 [1]
Eugongylinae morph 4	2 [2]	1 [1]	1 [1]	2 [2]
Eugongylinae morph 5	3 [3]	1 [1]	4 [5]
Sphenomorphinae
Sphenomorphinae indet.	6 [6]	9 [9]	26 [28]	22 [24]	5 [5]	3 [3]
Sphenomorphinae morph 1		2 [2]	2 [2]	1 [1]	3 [4]
Sphenomorphinae morph 2	1 [2]	1 [1]	7 [8]	1 [1]
Sphenomorphinae morph 3	5 [7]	5 [6]	12 [13]	10 [11]	5 [5]	1 [1]
Sphenomorphinae morph 4	1 [1]		2 [2]	1 [1]
Elapidae
Elapidae indet.	17 [17]	7 [7]	29 [41]	30 [47]	17 [23]	5 [6]
MNI [NISP]	130 [137]	76 [79]	209 [235]	158 [184]	74 [86]	30 [32]

FIGURE 5. A, relative abundances of order, and B, subfamily level of identification based on the minimum number of individuals (MNI) in the different sedimentary beds.

FIGURE 6. A, LOESS (local regression) fits of temperature (red) and aridity (blue) showing predicted values for the ages of the different sedimentary beds (triangles). Optimal smoothing parameters based on generalized cross-validation: α = 0.72 (temperature), α = 0.61 (% C4 grasses). B, correlations (linear models) of the different dimensions of the subfamily-level correspondence analyses and relative abundances of taxa (% of the minimum number of individuals belonging to a respective subfamily in the different sedimentary beds) with temperature and aridity. Darker shaded graphs indicate significance of linear models (p < 0.05). Shaded areas represent 0.95 level confidence intervals.

TABLE 3. Comparison of lizard taxa between the MDC deposit and contemporary habitat surrounding the cave (Robertson and Coventry 2019; ALA 2020).

	MDC	Robertson and Coventry	ALA
Amphibulorinae
Amphibolurinae indet. morph 1	x
Amphibolurus muricatus		x	x
Pogona barbata		x	x
Egerniinae
Liopholis sp. morph 1	x
Liopholis sp. morph 2	x
Liopholis whitii		x	x
Lissolepis coventryi		x	x
Tiliqua nigrolutea	x	x	x
Tiliqua rugosa		x	x
Eugongylinae
Acritoscincus duperreyi		x	x
Anepischetosia maccoyi		x
Eugongylinae indet. morph 1	x
Eugongylinae indet. morph 2	x
Eugongylinae indet. morph 3	x
Eugongylinae indet. morph 4	x
Eugongylinae indet. morph 5	x
Lampropholis guichenoti		x	x
Pseudemoia entrecastauxii		x	x
Sphenomorphinae
Eulamprus tympanum		x	x
Hermiergis peronii		x	x
Lerista bougainvillii		x	x
Sphenomorphinae indet. morph 1	x
Sphenomorphinae indet. morph 2	x
Sphenomorphinae indet. morph 3	x
Sphenomorphinae indet. morph 4	x
Pygopodidae
Aprasia striolata		x	x
No. of taxa	13	14	13

Kos, A. M. 2001. Stratigraphy, sedimentary development and palaeoenvironmental context of a naturally accumulated pitfall cave deposit from south-eastern Australia. Australian Journal of Earth Sciences 48:621–632.

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Robertson, P. and A. J. Coventry. 2019. Reptiles of Victoria. A Guide to Identification and Ecology. CSIRO Publishing, Clayton South, Victoria, Australia, 323 pp.

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Atlas of Living Australia. 2020. Available at http://www.ala.org.au. Accessed October 19, 2020.

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