The female genitalic morphology of “micronetine” spiders (Araneae, Linyphiidae)

Abstract

Current knowledge of ''micronetine'' female genitalia is almost exclusively based on transmitted light microscopy data. As such, our understanding of the epigynal anatomy is incomplete and somewhat misleading, to the extent that it hinders comparative studies of linyphiid diversity. We used scanning electronic microscopy (SEM) to study the complex epigynal morphology of ''micronetine'' spiders. Enzymatic digestion of soft tissues allowed us to examine the internal chitinized structures in detail using SEM. A taxonomic sample of nine species was selected to represent the morphological genitalic diversity of female ''micronetines'' (including one member of the Erigoninae clade). Results reveal that the epigynum consists of a pair of grooves formed by integument folds (copulatory and fertilization grooves). The protruding epigynal region is divided into a ventral and a dorsal plate by the grooves; both plates can be modified to form an epigynal cavity and/or a scape. Our observations confirm the widespread occurrence of epigynal grooves, rather than ducts, in ''micronetines''. Epigynal grooves seem to be common in linyphioids and other spider groups.

On the desmitracheate “micronetine” genus Nippononeta Eskov, 1992 (Araneae, Linyphiidae)

“…All examined specimens are deposited in the College of Life Sciences, Capital Normal University, China (CNU). Terminology of genital and somatic characters follows Tu and Hormiga (2010) and Hormiga (2000) respectively. Anatomical abbreviations used in the text and figures are:…”

“…The scaped epigynum in Nippononeta can be distinguished by its narrowed epigynal basal part covered by a transversal fold, the well developed stretcher and remnant lateral lobes (Fig. 2A–B), while in Agyneta the epigynal basal part is normal, the stretcher usually small or absent, but the lateral lobes are well developed bearing lateral pockets and copulatory openings (Tu and Hormiga 2010: fig. 6a).…”

“…Saaristo and Tanasevitch 2002a, b; Saaristo and Marusik 2004; Saaristo et al 2006; Tu et al 2006; Tu and Li 2006; Dupérré 2013; Sun et al 2014). Comparative studies show that a series of transitions exist among the forms of scaped epigynum (Tu and Hormiga 2010). Five characters were proposed to accommodate interspecific variation in tracheal anatomy (Miller and Hormiga 2004; Arnedo et al 2009).…”

A new cave-dwelling Centromerus from Sardinia (Araneae: Linyphiidae)

“…Nomenclature for the male palp is as in Gnelitsa (2007) and for the epigyne as in Hormiga & Tu (2010).…”

Revisão e análise cladística das espécies do gênero Moyosi Miller, 2007 (Araneae, Linyphiidae, Erigoninae)

“…Destes artigos, poucos se referem à biologia e filogenia, sendo a grande maioria limitada a estudos taxonômicos, como revisões de gêneros e descrições de espécies (Miller, 2005a(Miller, , 2005bDupérré et al, 2006;Saaristo, 2007;Lasut et al, 2009;Xu et al, 2010;Tu & Hormiga, 2010).…”