Zigrasimecia Abstract 2023

Zigrasimecia YKLP-AMB-002

This queen specimen was studied in astonishing detail through micro-CT scanning and had its external morphology described, as well as its internal organs in a work that demonstrate the power of this technique to help in the understanding of the morphology of the amber fossil ants (Zhuang et al., 2022b). In their description, the palpal formula is given as 4, 3, however, it can be seen to be in fact 6, 4 (Additional file 9, Video S8, 19 '').

The queen is surely not conspecific to Z. goldingot (one of the two species described based on queens), differing from it by the head rather subrectangular instead of subquadrate, by having 36 clypeal chaetae instead of 22, and by the shape of the mesoscutellum, which is about as long as wide while clearly wider than long in Z. goldingot. When compared to Z. tonsora (the other species described based on a queen), significant differences are not that apparent, in fact, both have similar clypeal chaetae numbers and similar mandibular shapes. Specimen YKLP-AMB-002 is better preserved than Z. tonsora holotype and has been better imaged due to the micro-CT scanning technique, so a detailed comparison between the two is difficult until we have a better characterization of Z. tonsora. Pilosity might be a main difference between the two, but chances of conspecificity should not be ruled out and direct comparison between them and/or further imaging of Z. tonsora should be attempted in the future.

Queen YKLP-AMB-002 was tentatively added to the multientry but not to the dichotomous key. The images in the multientry key are by Yuhui Zhuang, reproduced with permission.

Examined material. One alate queen (YKLP-AMB-002). Hukawng Valley, Kachin Province, Myanmar; Lower Cenomanian (ca.98.79 ± 0.62 Ma) [YKLP].