Diamonds in the rough: Ibotyporanga (Araneae, Pholcidae) spiders in semi-arid Neotropical environments

Abstract

Ninetinae are a group of small and short-legged pholcids that are largely restricted to dry habitats where they lead reclusive lives in and under objects on the ground. They have long been rare in collections and poorly studied. The genus Ibotyporanga Mello-Leitão, 1944 previously contained five species: four from the Brazilian Cerrado and Caatinga biomes, and one from northern Venezuela. Based on recent focused collecting in Brazil and northern Colombia, we describe 19 new species, all based on males and females: Ibotyporanga ziruma Huber sp. nov., I. walekeru Huber sp. nov., I. piojo Huber sp. nov., I. itatim Huber sp. nov., I. xakriaba Huber sp. nov., I. xique Huber sp. nov., I. camarai Huber sp. nov., I. kanoe Huber sp. nov., I. imale Huber sp. nov., I. sertao Huber sp. nov., I. guanambi Huber sp. nov., I. capivara Huber sp. nov., I. payaya Huber sp. nov., I. tuxa Huber sp. nov., I. atikum Huber sp. nov., I. kiriri Huber sp. nov., I. ouro Huber sp. nov., I. itajubaquara Huber sp. nov. and I. canudos Huber sp. nov. In addition, we describe the previously unknown females of I. diroa Huber & Brescovit, 2003, and I. ramosae Huber & Brescovit, 2003, and present comprehensive SEM data of eight species. We analyze CO1 barcodes of 41 Ibotyporanga specimens representing 21 described and one undescribed species. Genetic distances among specimens and a species delimitation analysis suggest that some nominal species may in fact represent two or more species. A first morphological cladistic analysis of the genus strongly supports the monophyly of Ibotyporanga and suggests several clades within the genus, including one that is characterized by a strong elongation of the male palpal procursus. Geographically, the genus shows a disjunct distribution in Brazil and northern South America, separated by the Amazon biome. While plesiomorphic taxa (with a short procursus) are found in both regions, derived taxa (with an elongated procursus) are limited to Brazil. Species distribution modeling suggests that Ibotyporanga might also occur in poorly sampled regions of Ecuador, Peru, and Venezuela. In addition, a strong sampling bias towards the proximity of access routes suggests that the genus is much more diverse even in Brazil and Colombia. Two karyotyped species shared the diploid number of 2n♂ = 30 and an X1X2X3Y sex chromosome system.