Untapped Potential: Systematics and Evolution of the African Toktokkie Beetle (Tenebrionidae: Sepidiini)

Sepidiini is a large and morphologically diverse tribe of darkling beetles (Tenebrionidae) in the subfamily Pimeliinae, containing ~1,000 species and subspecies. Despite the presence of many large and charismatic species and the cultural significance of some of its members, the toktokkie beetles, this tribe has been lacking revision at all taxonomic levels. To develop a framework for taxonomic revisionary work, in Chapter 1, I reconstructed a phylogeny of the tribe using targeted enrichment sequencing data. I also scored a comprehensive suite of diagnostic characters for the tribe to test in a phylogenetic context. Based on the results of the study, I proposed revising the subtribe Oxurina Koch, 1955, sens. nov. (now containing the genera Oxura Kirby, 1918, and Miripronotum Louw, 1979) and moving the genera Decoriplus Louw, 1979, Pterostichula Koch, 1952, Stenethmus Gebien, 1937b, and Synhimba Koch, 1952 to a new subtribe Stenethina subtr. nov. The tree topology also supports revising or synonymizing the genera Dichtha Haag Rutenberg, 1871, and Amiantus Fåhraeus, 1870, and revising the genus Somaticus Hope, 1840.

In Chapter 2, I performed a partial revision of the subtribe Hypomelina Koch 1955. A new genus Bufoniopsis gen. nov. is erected containing one newly described species Bufoniopsis hypnosis sp. nov. The genus Hypomelus Solier, 1843, and all of its species are redescribed, and three new species are described: Hypomelus johnprinei sp. nov., Hypomelus lorettalynnae sp. nov., and Hypomelus tomhalli sp. nov. One species was moved from Hypomelus to Triangulipenna Louw 1979 and redescribed, Triangulipenna vulipnus (Haag Rutenberg, 1873) comb. nov. Triangulipenna was redescribed and three new species were described, Triangulipenna tylerchildersi sp. nov., Triangulipenna dollypartonae sp. nov., and Triangulipenna ralphstanleyi sp. nov. A revised key to the genera of Hypomelina is provided as well as keys to the species of Hypomelus and Triangulipenna.

Toktokkie beetles—members of the subtribe Molurina Solier, 1843—are known for their substrate tapping behavior which is a form of sexual communication in which beetles tap their abdomens on the ground to locate mates. Despite the fact that this behavior is well-known among people in southern Africa, very little research has been done on the topic. In Chapter 3, I document variation in tapping patterns across the subtribe Molurina. Three characters of tap trains were found to vary: length of tap trains, tapping rate, and tapping pattern. Ancestral state reconstruction was performed for each of the characters. Characters were found to be only partially linked to ancestry. Additionally, in any given locality sampled, no two species had the same “song”. This suggests that signal partitioning could be influencing species “songs”.