Two new thorny stick insects (Euphasmatodea) from mid-Cretaceous Kachin amber

Two new species of thorny stick insects are described and figured, belonging to the genus Echinosomiscus Engel, 2016 (Euphasmatodea: Phasmatidae: Echinosomiscinae). Echinosomiscus conicaculeatus sp. nov. and E. longianalis sp. nov. are both from mid-Cretaceous Kachin amber and preserve apomorphies of this genus, such as the similar coronal acanthae on the head, a scape with two dorsal thorns, thoracic spines arranged transversely, and tarsomere V longer than the remaining tarsomeres. These two new species have different and distinctive arrangements of acanthae on the head, thorax, and legs relative to E. primoticus Engel & Wang, 2016. Most notably, E. longianalis lacks spines on the abdomen, and tergum X is undivided vs. numerous spines on the abdomen, and tergum X divided into hemitergites in E. primoticus. The discovery of these new specimens broadens the evidence of spines as a defensive mechanism in the mid-Cretaceous forest ecosystems.