New Proposal of Setal Homology in Schizomida and Revision of Surazomus (Hubbardiidae) from Ecuador

Abstract

The homology of three somatic systems in Schizomida is studied yielding the following results: (1) proposal of homology and chaetotaxy of abdominal setae in Surazomus; (2) revision of the cheliceral chaetotaxy in Schizomida, with suggestion of new homology scheme between Hubbardiidae and Protoschizomidae, description of a new group of setae in Hubbardiinae (G7), and division of setae group 5 in two subgroups, G5A and G5B; (3) proposal of segmental homology between trimerous and tetramerous female flagellum in Hubbardiinae with association of segment III of tri-segmented species to segments III + IV of tetra-segmented species. Considerations about the dorsal microsetae on the male flagellum are made. The genus Surazomus in Ecuador is revised. The sympatric species Surazomus palenque sp. nov. and S. kitu sp. nov. (Ecuador, Pichincha) are described and illustrated. The female of S. cuenca (Rowland and Reddell, 1979) is described, with two new distributional records for the species. Surazomus cumbalensis (Kraus, 1957) is recorded for the first time from Ecuador (Pichincha).

Description of a new species of Surazomus (Arachnida: Schizomida), with comments on homology of male flagellum and mating march anchorage in the genus

“…* Villarreal et al . [13] found another pair of Dm3 microsetae. This second pair was referred as Dm3B and the original Dm3 as Dm3A.** Monjaraz-Ruedas et al .…”

“…The anchoring mechanism is still poorly understood, but the male flagellum is certainly sexually selected, as it has diverse forms throughout the order, rendering them useful in systematics [ 8 , 9 , 10 ]. Albeit diverse, the flagellum of schizomids bears multiple setae that are mostly constant within species and are present across the major taxonomic groups, being largely used in species descriptions and hypotheses of setal homology since the 1990s [ 11 , 9 , 12 , 13 , 14 ]. Recently, Monjaraz-Ruedas et al .…”

“…Presently Surazomus Reddell & Cokendolpher, 1995 (Hubbardiidae: Hubbardiinae) includes 24 species distributed through Central and South America: seven species from Costa Rica, seven from the Andean foothills and ten from the Amazon region [ 3 , 13 , 17 , 18 ]. Within Surazomus we find different types of male flagella: some species have a rounded flagellum, such as Surazomus chavin Pinto-da-Rocha, 1996 and Surazomus uarini Santos & Pinto-da-Rocha, 2009 (see Armas [ 3 ]: figs 13A and 19A); many have a trilobed flagellum bearing a pair of membranous dorso-submedian eminences, with the median portion of the flagellum laterally widened (e.g.…”

Rowlandius dumitrescoae species group: new diagnosis, key and description of new cave-dwelling species from Brazil (Schizomida, Hubbardiidae)

“…Terminology of pedipalps, legs and spermathecae follows Reddell and Cokendolpher (1995) and Moreno-González et al (2014); flagellum setation follows terminology of Harvey (1992), modified by Cokendolpher and Reddell (1992), Villarreal et al (2014), Moreno-González et al (2014) and Monjaraz-Ruedas et al (2016); cheliceral setation terminology is based on Lawrence (1969) modified by Villarreal et al (2016). Description format follows Villarreal et al (2016). The terms α- and β-males are used here for the two different sizes of heteromorphs.…”

“…Males are unknown for Rowlandius sul and this species was not included in the male key. The preparation and illustrations of the spermathecae follow Villarreal et al (2016). Dorsal, ventral, and lateral photos were made with a Leica MZ16 microscope attached to a FujiFilm X10 camera.…”