The dorsal chaetotaxy of Trogolaphysa (Collembola, Paronellidae), with descriptions of two new species from caves in Belize

Felipe Soto-Adames,Steven Taylor

doi:10.3897/zookeys.323.4950

Abstract

Species diagnosis in Trogolaphysa has been based, until now, almost exclusively on number of eyes and shape of claws and mucro. Chaetotaxy, a character system important to diagnose species in other genera of scaled Entomobryoidea, has been described only for a few Trogolaphysa species. Here the complete dorsal chaetotaxy of six species of Trogolaphysa is described using the AMS and Szeptycki’s systems for head and body, respectively. A morphology-based parsimony analysis was performed to evaluate whether chaetotaxic characters overcome the influence of putatively cave adaptive convergent characters to resolve species level relationships, and to evaluate the evolution of the dorsal macrochaetae of the head. Phylogenetic analysis using only putative cave-adaptive characters support clades of unrelated taxa, but the addition of chaetotaxy overcomes the influence of convergent characters. A phylogeny based on all characters supports a trend towards reduced head macrochaetae number. Head macrochaetae are lost beginning with A3 and followed, in order, by S5, S3 and M3. In addition, a checklist of New World Trogolaphysa is provided and two new species, Trogolaphysa giordanoae sp. n. and Trogolaphysa jacobyi sp. n., are described on the basis of material collected in six caves in southern Belize.

Highlights

The collembolan fauna of Belize is among the least known of any Central American country
Abbreviations used for names are: Avelardo Canti (AC), Gabriel Chaco (GaC), Germano Coe (GeC), William R
The dorsal chaetotaxy of Trogolaphysa has not been fully described in the context of the AMS (Soto-Adames 2010) and Szeptycki (1979) systems of nomenclature

Summary

Introduction

The collembolan fauna of Belize is among the least known of any Central American country. What is understood about the evolution of morphological adaptations to cave habitats in entomobryoid springtails is derived from northern temperate members of the genera Pseudosinella and Sinella (Christiansen 1961, Gama 1984). The characters utilized in the descriptions of most of the 33 species of Trogolaphysa reported from the New World (Mari Mutt and Bellinger 1990, Mari Mutt et al 2009; Table 1) are limited to claw complex and mucronal shape (e.g., Palacios-Vargas et al 1985[1986]), two character systems prone to convergent evolution in cave habitats (Christiansen 1961, Christiansen and Culver 1987). While convergence itself is of interest in understanding evolution in caves (Derkarabetian et al 2010, Hedin and Thomas 2010), distinguishing convergent characters adaptive for subterranean life from characters that better reflect phylogenetic history has proven to be important in a variety of groups of animals (e.g., Wiens et al 2003)

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