Varanopid from the Carboniferous of Nova Scotia reveals evidence of parental care in amniotes


Here we report on a fossil synapsid, Dendromaia unamakiensis gen. et sp. nov., from the Carboniferous period of Nova Scotia that displays evidence of parental care—approximately 40 million years earlier than the previous earliest record based on a varanopid from the Guadalupian (middle Permian) period of South Africa. The specimen, consisting of an adult and associated conspecific juvenile, is also identified as a varanopid suggesting parental care is more deeply rooted within this clade and evolved very close to the origin of Synapsida and Amniota in general. This specimen adds to growing evidence that parental care was more widespread among Palaeozoic synapsids than previously thought and further provides data permitting the identification of potential ontogeny-dependent traits within varanopids, the implications of which impact recent competing hypotheses of the phylogenetic affinities of the group.

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Fig. 1: Locality and horizon information for D. unamakiensis gen. et sp. nov. (NSM017GF020.001).
Fig. 2: Photographs of D. unamakiensis gen. et sp. nov. (NSM017GF020.001).
Fig. 3: Illustrations of D. unamakiensis gen. et sp. nov. (NSM017GF020.001).
Fig. 4: Photographs of the small individual of D. unamakiensis gen. et sp. nov. (NSM017GF020.001).
Fig. 5: Time-calibrated strict consensus tree from the parsimony-based phylogenetic analysis including D. unamakiensis gen. et sp. nov. (NSM017GF020.001).

Data availability

Specimen NSM017GF020.001 is accessioned in the Nova Scotia Museum. See Supplementary Information and Dataset for character list and character–taxon matrix used in the currently analyses.


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We thank T. Fedak, M. Grey, K. Ogden and staff at the Nova Scotia Museum for facilitating the loan of this material. We also thank S. W. McKeane and Provincial staff for assistance with permits. We thank J. Calder, D. Scott, J. Pardo, B. Gee, R. Hook, S. Modesto and R. Reisz for discussions. We thank D. Gray for assistance in the field. We acknowledge our field site is located in Mi’kma’ki territory of the Mi’kmaq people. Funding was provided in part by the Natural Sciences and Engineering Research Council of Canada discovery grant (no. 04633 to H.C.M.).

Author information

H.C.M. was principal investigator. B.H. discovered the specimen. A.M. and H.C.M. prepared and illustrated the specimen. All authors contributed to discussion, preparation and writing of the manuscript.

Correspondence to Hillary C. Maddin.

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The authors declare no competing interests.

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Supplementary information

Supplementary Information

Character list and Supplementary Figs. 1 and 2.

Reporting Summary

Supplementary Dataset

Character–taxon matrix.

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Maddin, H.C., Mann, A. & Hebert, B. Varanopid from the Carboniferous of Nova Scotia reveals evidence of parental care in amniotes. Nat Ecol Evol 4, 50–56 (2020).

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