Nopyllus , a new South American Drassodinae spider genus ( Araneae , Gnaphosidae )

Nopyllus gen. nov. is proposed to include Apopyllus isabelae Brescovit & Lise, 1993 and Nopyllus vicente sp. nov. from southern Brazil. Nopyllus gen. nov. is close to Apodrassodes Vellard, 1924 and Apopyllus Platnick & Shadab, 1984, can be distinguished from both genera by the absence of a dorsal abdominal scutum in males, the absence of a median apophysis on bulb, the curved, narrow and reniform cymbium, and by the presence of a very conspicuous cymbial basal projection.

The genus Apopyllus is nowadays represented by nine Neotropical species.The genus was proposed by Platnick & Shadab (1984) and since then, only one species was added to the genus, namely A. isabelae Brescovit & Lise, 1993.According to Platnick & Shadab (1984), Apopyllus is most probably related to Apodrassodes due to the elongate embolus supported by a membranous tegular extension at the male palp.However, female genitalia are not quite similarly shaped in both genera, presenting smaller plates and long coiled ducts in Apopyllus and a rather larger plate and less coiled ducts with an anterior excavation covered by a short protuding scape in Apodrassodes (Platnick & Shadab, 1983, 1984).
Examining the gnaphosid material from Southern Brazilian museum collections, large number of Apopyllus specimens were found.However, my attention was particularly directed to some smaller and pale male specimens from Vicente Dutra country, in the state of Rio Grande do Sul.These specimens show male palp features very similar to those described for A. isabelae, including the absence of the "characteristic Apopyllus median apophysis" (breScovit & liSe, 1993:110, figs 8, 9).After a closer examination of these specimens and the holotype of A. isabelae, it seemed that the males found at Rio Grande do Sul belong actually to an undescribed species.Based on the absence of median apophysis, on the inconspicuous "cymbial incision" sensu Platnick & Shadab (1984:6, figs 11, 12), presence of a cymbial basal projection, presence of a groove in almost the entire extension of the retrolateral border of cymbium covered with angular setae, and absence of dorsal abdominal scuta in all the examined males, it is proposed a new genus to include both species
Incident light images were taken through a stereomicroscope and compound microscope with an attached digital camera and processed with Helicon Focus multi-range program.Drawings were made using DOI: 10.1590/1678-476620141042252261 Iheringia, Série Zoologia printed image as model and compound microscope and stereomicroscope as three dimensional shape confirmation tools.Electron scanning microscope (SEM) images were taken using a Jeol-JSM-5200 with attached SLR digital camera.Before mounting SEM material was prepared using 80-90-100% Ethanol sequence and by last step drying out in a small vial containing a small piece of cotton imbibed with Ether, for 24 hours.Posteriorly to the mounting process, stubs were dried out for 24 hours under a normal tungsten filament lamp.Apopyllus cf.silvestrii (Simon.1905) scanning material from Roça da Estância, Mampituba, RS, Brazil, 01.XI.2006, A. Gonçalves leg. (MCN 49397).1,carapace,dorsal;2,abdomen,dorsal. Left palp: 3,prolateral;4,ventral;5,retrolateral;6,palpal tibia,retrolateral;7,bulb,posterior (cpd,cymbial  Etymology.The generic name is a contraction between "no" (English negative term) and the generic name Apopyllus, and is masculine in gender.
Diagnosis.Nopyllus vicente sp.nov.can be recognized and distinguished from N. isabelae comb.nov.by the RTA ventral process stout, with oblique distal end and the dorsal one narrow and sharply pointed (Figs 32,39,40).
Distribution.Known only for the type locality.

DISCUSSION
According to Platnick (1990) there is no generally accepted subfamilial classification for the Gnaphosidae, being Drassodinae used merely as "wastebasket…for genera which do not obviously belong to other subfamilies".However, Apodrassodes and Apopyllus are placed by the same author at Drassodinae.MurPhy (2007) tried another approach for grouping the Gnaphosidae genera and placed both genera in a group named "Echemus group".He characterized this group by the plain colored abdomen and by the males with dorsal abdominal scutum.The absence of dorsal scutum in males of Nopyllus do not agree with Murphy's "Echemus group" characters.Anyway, as stated by MurPhy (2007), this grouping proposition is only "for identification purpose" and it may not reflect the evolutionary relationships between genera.According to Platnick & Shadab (1984) Apodrassodes and Apopyllus are closely related based on the presence of a long embolus and a membranous tegular extension.Since the genus described here also presents these structures (but see discussion about the homology of tegular extension below), it could be related to Apodrassodes and Apopyllus.The absence of a dorsal scutum in Nopyllus could be a secondary loss.This question, however, can only be answered after a formal phylogenetic analysis of gnaphosid genera.
The presence of a median apophysis in Apodrassodes was noted by Platnick & Shadab (1983) but is not diagnosed in Apopyllus by Platnick & Shadab (1984).However, the presence of a median apophysis at the male palp bulb in Apopyllus seems to be obvious, as an usually long, well sclerotized and hooked structure originating from the tegulum near the base of the embolus (see Platnick & Shadab, 1984:3, 6;figs 1, 11).Both genera presents only two accessory structures to the embolus, the "tegular extension", originating from the anterior portion of tegulum (well developed in Apopyllus and reduced in Apodrassodes), and the tegular median apophysis, arising from tegulum near the embolus base.The latter sclerite is conspicuous in Apopyllus and somewhat hidden by the embolus in Apodrassodes.
In Nopyllus only a single structure accessory to the embolus can be found: a membranous, elongated and grooved structure (Figs 13,14,34,(36)(37)(38).Although it was also identified as the "tegular extension" in this paper, it apparently does not originates at the anterior portion of the tegulum (Figs 13,14,34,36) as in Apodrassodes and Apopyllus (Figs 42,46,47).In Nopyllus the referred structure originates retrolaterally to the tegulum, near the embolus base (Figs 34,36), in a similar placement as expected for the "tegular median apophysis" of Apopyllus (Figs 42,43,46), but it seems not to share its shape or function.The possible homology between "tegular extension" and "conductor" should be also considered.In most cases the conductor should be a well recognizable sclerite at Gnaphosidae male palp bulb, rather as the median apophysis which can be present or absent (ubick et al., 2005).
The cymbial incision observed in Apopyllus species (Figs 41,44) is apparently reduced (Fig. 35) with the cymbial proximal portion strongly modified into the cymbial basal projection in Nopyllus (Figs 8,9,11), as noted by breScovit & liSe (1993:106).The main function of the cymbial incision or cavity in Apopyllus seems to be the accommodation of terminal embolus loop (Platnick & Shadab, 1984:2).In the case of Nopyllus the accommodation of the embolus loop seems to be regarded to cymbial basal projection that acts probably in similar way of a "paracymbium".In Nopyllus the RTA is also quite differently shaped than in Apopyllus.In the former the RTA is represented by two relatively simple processes (Figs 17,40) and in the latter the RTA is folded and complex, also very possibly with an embolus supporting function (Fig. 45; see also Platnick & Shadab, 1984:2, 3;figs 1, 2).
Based on the very long embolus and the strongly Iheringia, Série Zoologia, Porto Alegre, 104(2):252-261, 30 de junho de 2014 modified cymbium it is suggested that Nopyllus is closer to Apopyllus than to any other neotropical gnaphosid.
Apopyllus still holds a possible synapomorphy that is not shared with Nopyllus, the typical folded RTA.Nopyllus also have some presumptive exclusive characters, like the curved and narrow reniform cymbium with retrolateral groove covered by angular curved setae and the sharp pointed scales at antero-retrolateral portion of tegulum.