Phylogeography of the endemic grasshopper genus Betiscoides (Lentulidae) in the South African Cape Floristic Region.

Vicariance and dispersal are two important processes shaping biodiversity patterns. The South African Cape Floristic Region (CFR) is known for its high biotic diversity and endemism. However, studies on the phylogeography of endemic invertebrates in this biodiversity hotspot are still scarce. Here, we present a phylogenetic study of the flightless grasshopper genus Betiscoides, which is endemic to the CFR and strongly associated with restio plants (Restionaceae). We hypothesized that the genus originated in the southwestern part of the CFR, that differentiation within the genus is mainly an effect of vicariance and that the three known species only represent a minor fraction of the real genetic diversity of the genus. We inferred the phylogeny based on sequences of three mitochondrial and two nuclear genes from 99 Betiscoides specimens collected across the CFR. Furthermore, we conducted a SDIVA analysis to detect distributions of ancestral nodes and the possible spatial origin of these lineages. Strong differentiation among genetic lineages was shown. The ancestor of this genus was most likely distributed in the southwestern CFR. Five major lineages were detected, three of which were ancestrally distributed in the southwestern CFR. The ancestors of the two other lineages were distributed in the northern and eastern margins of the CFR. A total of 24 divergent evolutionary lineages were found, reflecting the geographical isolation of restio-dominated fynbos habitats. Dispersal played a more prominent role than expected in differentiation of Betiscoides. While the five main lineages were separated during a first phase via dispersal, differentiation occurred later and on smaller spatial scale, predominantly driven by isolation in montane refugia (i.e. vicariance). Our study also suggests that flightless insect taxa likely show high levels of differentiation in biodiversity hotspots with their taxonomy often being incomplete.

A preliminary phylogeny of the South African Lentulidae.

BACKGROUND: The grasshopper family Lentulidae is endemic to eastern and southern Africa, with its center of diversity situated in South Africa, the highest diversity being found in the Cape Floristic Region, which is one of the global biodiversity hotspots. The family consists of 35 genera sorted in two subfamilies. This study provides first insights into the phylogeny of Lentulidae. Two mitochondrial genes (12S and NDS) were sequenced and the phylogeny was inferred through Maximum Likelihood and Bayesian Inference. RESULTS: Our results indicate that the current classification into the subfamilies Lentulinae and Shelforditinae may be incorrect as Uvarovidium, Leatettix (Shelforditinae) and Devylderia (Lentulinae) clustered together in one main clade, while Betiscoides, Basutacris and Gymnidium (all Lentulinae) formed the second main clade. The genera Uvarovidium and Leatettix, which had been assigned to the Acrididae (subfamily Hemiacridinae) in the past, grouped within the Lentulidae, confirming their current assignment to this family. The East African Usambilla group is likely to represent a sister clade to the south African Lentula and Eremidium. Diversification patterns in the genus Devylderia and Betiscoides suggest a higher number of species than currently known. CONCLUSIONS: Our phylogeny is not in line with the current systematics of Lentulidae, suggesting that a broader sampling and a study of the genitalia would be useful to clarify the taxonomy. Furthermore, some genera (particularly Betiscoides and Devylderia) are in need of taxonomic revision, as the number of species within these genera is likely to be higher than the current taxonomy suggests.