Carinasquama, new gecko from Cretaceous of Myanmar, with male anatomy (free pdf)

[Ben Creisler]

Ben Creisler

bcre...@gmail.com

A new paper:

Free pdf:

Carinasquama rusmithii gen. et sp. nov.

Juan D. Daza, Emily G. Selling, Kelsey M. Jenkins, Edward L. Stanley, Daniel S. Doucet, Gabriela Fotanarrosa & Aaron M. Bauer (2026)
Evidence of male anatomy in a mid-Cretaceous Burmese miniaturised amber gecko.
Swiss Journal of Palaeontology 145: 785-799.
doi: https://doi.org/10.3897/sjp.145.188227
https://sjp.pensoft.net/article/188227/



Palaeontologists use skeletal features to determine the sex of specimens, but this can be complicated due to the incompleteness of fossil remains. In fossil assemblages, sexual dimorphism may be present in the form of ornamentation or may occasionally be detected through multivariate analyses. Sex can sometimes be estimated when embryos or eggs are found within a female specimen or associated with the specimen (e.g. brooding behaviour), although other sex-specific traits are rarely preserved in fossils. Squamates exhibit hemipenal bulges that are externally observable in males. These structures typically do not leave traces in hard rock fossils, but may be preserved in amber. We describe two lizard specimens embedded in burmite amber, which preserve almost the entire integument, though skeletal remains are very incomplete. One specimen shows a swelling at the base of the tail, comparable to the hemipenal bulge in male squamates, suggesting the presence of paired copulatory organs or hemipenes. Hemipenes almost certainly originated in the ancestor of Squamata or in stem-Squamates during the Triassic Period and this fossil provides rare documentation of these structures in the mid-Cretaceous. Research on amber fossils continues to highlight the remarkable preservation of soft tissues, even when hard tissues are poorly preserved. In this paper, we followed high ethical standards for sourcing these controversial fossils, following the recommendations from the Myanmar working group of the Society of Vertebrate Paleontology.

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