Homology and morphology in Poduromorpha (Hexapoda, Collembola)

Abstract

Abstract. The detailed external morphology and general anatomy of the majority of families and subfamilies of Poduromorpha were investigated and compared. This examination was done in relation to the three remaining orders of Collembola: Entomobryomorpha, Symphypleona and Neelipleona. Within Poduromorpha, homologies among the different families and subfamilies are established for general chaetotaxy, and chaeotaxy of head, buccal cone, sensilla of fourth antennal segment, anal valves and tibiotarsus. A consistent and comprehensive nomenclature is proposed for these morphological features unifying those applied in scattered existing studies. Observations on first instars are reported. Comparison of first instars and adult chaetotaxy suggests a possible paedomorphic trend in the evolution of Poduromorpha.

Suitability of cuticular pores and sensilla for harpacticoid copepod species delineation and phylogenetic reconstruction

“…Unfortunately, there has never been a phylogenetic reconstruction of crustaceans, nor any groups thereof, based on cuticular organs, despite the fact that many studies have advocated this potential and proposed some groupings based on intuitive methods (Puri, 1974;Mauchline, 1988;Tsukagoshi, 1990;Olesen, 1996;Høeg and Kolbasov, 2002). This is in stark contrast with taxonomic and phylogenetic practices in some other groups of small animals with a rigid integument, such as, for example, insects (Bousquet and Goulet, 1984;Alarie, 1995Alarie, , 1998D'Haese, 2003;Faucheux et al, 2006), tardigrades (Nichols et al, 2006), and kinorhynchs (Nebelsick, 1992;GaOrd oñez et al, 2000;Sørensen et al, 2012).…”

A new species of Uralaphorura Martynova, 1978 from northeast China, with a key to world species of the genus (Collembola, Onychiuridae)

“…Labium areas and chaetal nomenclature follow Massoud (1967) in D’Haese’s (2003) modification. Chaetae on anal valves are named following Yoshii (1996).…”

An application of dynamic homology to morphological characters: direct optimization of setae sequences and phylogeny of the family Odontellidae (Poduromorpha, Collembola)

“…Homology hypotheses between outgroup and ingroup species are based on D’Haese’s (2003a) comprehensive morphological study of Poduromorpha Collembola.…”

“…Collembola systematics heavily depends on the usage of characters provided by the setae (see reviews in D’Haese, 2003a and Deharveng, 2004), especially below the familial rank. The study of the number, nature, shape and position of setae is called chaetotaxy (sensu Cassagnau, 1990; chap.…”

“…Obviously, this would not be a real practical issue if the positions of the setae were trivial and complied with the traditional scheme. However, numerous examples from real life observations show setae do not always fit in the scheme, and their correspondences can actually appear quite puzzling (see for example the discussion on homology for the sensilla of the fourth antennal segment in D’Haese, 2003a,b). We illustrate some of those drawbacks with the work of Arbea and Jordana (1997) on Iberian Odontellidae.…”