Chaetotaxy of first-instar Campylothorax sabanus (Wray), and description of three new Campylothorax species from Hispaniola (Collembola, Paronellidae)

ABSTRACT

The dorsal chaetotaxy of adult Campylothorax species is considerably reduced, making homology determinations difficult. Previous studies demonstrated that homology of the adult chaetotaxy can be established by analysis of the primary chaetotaxy of first-instar larvae. The goals of the present study are to provide a description of the complete dorsal chaetotaxy of first-instar C. sabanus (Wray, 1953) in order to evaluate the homology of elements recently proposed for adult Campylothorax, to evaluate new morphological characters useful to diagnose species, and to report on the species of Campylothorax on the Greater Antillean island of Hispaniola. As a result of the analysis of primary chaetotaxy it is concluded that: (1) on thorax (Th.) 2 chaeta p4 is incorporated (as a multiplet) into the p3 complex, whereas the latero-external microchaeta corresponds to p6e; (2) on abdomen (Abd.) 3 the lateral mesochaetae belong to series 7 (i.e., a7, m7 and p7); (3) on Abd. 4 the inner macrochaetae correspond to A3, A5, A6, B3, B4, and B5, the inner posterior bothriotrix, corresponds to B6, whereas T6 is displaced laterally towards row D. Aspects of the chaetotaxy that remain unclear are the identity of chaetae along the inner margin of the eyes, and the homology of the two anterior macrochaetae on Th. 3. New morphological characters useful in species diagnosis revealed by comparative analysis are the number of head macrochaetae in series S, number of meso- and metathoracic macrochaetae and number and identity of latero-external macrochaetae on the fourth abdominal segment. Analysis of Campylothorax from Hispaniola reveals the presence of four species: C. cubanus Gruia, 1983 previously known only from Cuba, and three species new to science – C. notidanus sp. nov., C. hexosetosus sp. nov. and C. dominicanus sp. nov.

KEYWORDS:

• West Indies
• biogeography
• Entomobryoidea
• Puerto Rico
• comparative morphology

Acknowledgements

I would like to thank Robert Davidson and John Rawlins (Carnegie Museum of Natural History, Pittsburgh) for material from the Dominican Republic, and Ross Bell (University of Vermont) for the material of C. cubanus from Haiti. I also thank Héctor Soto-Sanabria for his assistance during field collections in Puerto Rico. I would like to acknowledge the constructive comments made by two reviewers whose contributions were important in improving the ideas presented here.

Disclosure statement

No potential conflict of interest was reported by the author.