Are Scelimeninae (Orthoptera: Tetrigidae) Monophyletic and Why it Remains a Question?

Abstract

Spiky pygmy grasshoppers (Scelimeninae) are a large subfamily within Tetrigidae that include three tribes (Criotettigini, Scelimenini, Thoradontini). Their systematic relationships within Scelimeninae were not and are still not well understood, nor is their relationship to other Tetrigidae subfamilies. Chen et al. (2018) published a study on the phylogenetic relationships among Scelimeninae genera. Chen et al. (2018) (1) did not question the monophyly of Scelimeninae; (2) included only Chinese representatives into analysis; (3) probably misidentified some material used in analysis, (4) did not make sequences publicly available, and (5) did not highlight certain important findings. Scelimeninae are not monophyletic, but a polyphyletic group composed of genera gathering species with spiky lateral lobes. Spiky lateral lobes are a homoplastic character. Scelimenini are an Oriental group including about 100 species and 15 genera. Criotettigini and Thoradontini should not be assigned to Scelimeninae, but remain without subfamily placement. Numerous Chinese taxa are synonymous based on morphological comparison and Chen et al. (2018) molecular data: Criotettix brevipennis Zheng et Xie, 2002 = C. strictvertex Zheng, Wei et Li, 2009 syn. nov. and = C. yingjiangensisZheng et Ou, 2011syn. nov., Paragavialidium hainanense (Zheng et Liang, 1985) = P. tridentatumZheng, 1994syn. nov. and = P. platynotum Zheng et Xu, 2010 syn. nov., Thoradonta yunnanaZheng, 1983 = T. dianguiensis Deng, Zheng et Wei, 2006 syn. nov., = T. lancangensis Zheng, 1991 syn. nov., = T. longipenna Zheng et Liang, 1991 syn. nov., = T. obtusilobata Zheng, 1996 syn. nov. and = T. transpicula Zheng, 1996 syn. nov. There is no morphological (nor molecular) apomorphy pointing to traditional Scelimeninae monophyly. Furthermore, Criotettix telifera is transferred to the genus Afrocriotettix and the new combination is A. teliferus (Walker, 1871) comb. nov.; a new name, Dengonius Adžić et al. nom. nov. (and Dengonius dinghuensis (Liang, 1995) comb. nov.) is proposed for monotypic genus Cyphotettix Liang, 1995 (nomen nudum BentotettixDeng, 2016), homonym of Cyphotettix Rehn, 1952; and Eufalconoides tridentatusZheng, Li et Shi, 2003syn. nov. is found to be a nymph of Scelimena melli Günther, 1938, resulting in synonymy of the genus EufalconoidesZheng, Li et Shi, 2003syn. nov. with ScelimenaServille, 1838 and a new combination, Scelimena guizhouensis (Zheng et Shi, 2006) comb. nov.