Friday 6 October 2017

Santanmantis axelrodi: A new specimen of a Cretaceous Mantis.

Praying Mantises (Mantodea) are large carnivorous Insects related to Cockroaches and Termites. They are easily recognised for their large, highly modified forelegs, which are no longer used for locomotion but instead used to strike rapidly and snatch prey. Mantises are well known in popular culture for the habit, seen in the females of some species, of consuming the males during mating, although as a group they show a wide range of behavioural and physical adaptations. The oldest known fossil Mantis comes from the Late Jurassic of Mongolia, with the group diversifying during the Cretaceous and Early Tertiary. One important Mesozoic locality for Mantises is the Early Cretaceous Crato Formation of Brazil, a fossil lagerstatte known for its numerous exceptionally well preserved Insects. Two species of Mantis have been described from the Crato Formation, the rather Cockroach-like Raptoblatta waddingtonae, and the slightly more modern-appearing  Santanmantis axelrodi.

In a paper published in the journal PeerJ on 24 July 2017, Marie Hörnig of the Zoological Institute and Museum at Ernst-Moritz-Arndt Universität Greifswald, and Joachim Haug and Carolin Haug of the Biocenter, Department of Biology II and GeoBio-Center at Ludwig-Maximilians-Universität München, describe a new specimen of Santanmantis axelrodi from the Crato Formation.

The new specimen comprises the head, forewings and forepart of the thorax of the Insect, preserved in dorsal view. The specimen is confirmed as belonging to Santanmantis axelrodi on the basis of its wing venation, though its wings show it to be considerably larger than any previously described specimen with a forewing of 16 mm, compared to 10-13 mm in those specimens. Interestingly the specimen has preserved spines on its second pair of legs, something which is found in modern Mantises, and helps with prey capture, but which had not previously been seen in Santanmantis axelrodi.

New specimen of Santanmantis axelrodi. (A) Overview. (B) Colour-marked version of (A); dark blue: eyes, yellow: head capsule, brown: tergite of thorax segment 1 (pronotum), orange: prothoracic femur, purple: prothoracic tibia, dark green: mesothoracic coxa, indigo: mesothoracic trochanter, blue: mesothoracic femur, light green: mesothoracic tibia, red: spines. (C) Detail of appendage of thorax segment 2, same colour code as in (B). Hörnig et al. (2017)

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