Description of three new species of Aposphragisma Thoma, 2014 (Araneae: Oonopidae) from Sumatra, Indonesia

Abstract Three species from the family Oonopidae are newly described from leaf litter habitats in Sumatra, Indonesia based on male and female morphology. All three species belong to the genus Aposphragisma Thoma, 2014: Aposphragismaglobosumsp. n., Aposphragismajambisp. n., and Aposphragismasumatrasp. n.


Introduction
The family Oonopidae Simon, 1890 is a diverse group of spiders with over 1801 described species in 114 genera from all over the world (World Spider Catalog 2018). Oonopids are small (1-4 mm), two-clawed, ecribellate spiders (Saaristo 2001, Jocqué andDippenaar-Schoeman 2007) that can be abundant in leaf litter, under bark of trees, in forest canopies and in subterranean habitats (Burger et al. 2002;Harvey and Edward 2007;Fannes and Jocqué 2008;Baehr et al. 2010). Currently 42 species of Oonopidae belonging to eight genera are known to occur in Indonesia, excluding Borneo (World Spider Catalog 2018). More than half of the species can be found on Sumatra (23 species), as well as most of the genera (six genera). The most speciesrich genus, Ischnothyreus Simon, 1893 was recently revised by Richard et al. (2016) with eight species occurring on the island. It is followed by the genera Gamasomorpha Karsch, 1881 and Prethopalpus Baehr et al. 2012 (with six species each) revised by Eichenberger et al. (2011) and Baehr et al. (2012), respectively.
In 2014, Thoma described the new South East Asian genus Aposphragisma Thoma, 2014 including 19 new species, from which only one species was described from Sumatra, A. borgulai Thoma, 2014(Thoma et al. 2014). Here we present the description of three new species of Aposphragisma from Sumatra.

Material and methods
All specimens were collected in the framework of the EFForTS (Ecological and Socioeconomic Functions of Tropical Lowland Rainforest Transformation Systems) project that investigates the effects of transformation of lowland rainforests into agricultural systems (Drescher et al. 2016). Samples were taken from four forest types (primary degraded lowland rainforest, agroforest with a mixture of native vegetation and planted rubber trees (secondary degraded lowland rainforest), rubber monoculture, and oil palm monoculture). Material was collected during three sampling campaigns. The first was conducted in October-November 2012 (Barnes et al. 2014). From each of 32 sampling sites, three samples of 1×1 m were taken by sieving the leaf litter through a sieve of 2-cm mesh. Spiders visible by eye were hand-collected and stored in 65% ethanol. The second campaign was conducted in October-November 2013 (Klarner et al. 2017). From the same sampling sites three soil samples of 16×16 cm were taken with a spade, comprising the litter layer and the underlying mineral soil to a depth of 5 cm. Finally, the third collecting round was conducted in March, June, September and December 2017; specimens were collected by sieving 16×16cm of litter. All spiders from soil and litter were extracted by heat (Kempson et al. 1963) and collected in a dimethyleneglycol-water solution (1 : 1) and thereafter transferred into 70% ethanol. The material examined is deposited in the following institutions: Indonesian Institute of Sciences Cibinong, Indonesia (LIPI); Zoological Museum Hamburg, Germany (ZMH).
Specimens were examined in 65-75% ethanol under a Leica M125 dissection microscope and photographed with a custom-made BK Plus Lab System by company Dun, Inc. with integrated Canon camera, macro lenses (65 mm and 100 mm) and the Zerene stacking software (Zerene Systems LLC 2018). Female genitalia were excised using a sharp entomological needle, treated with Pancreatin (Álvarez-Padilla and Hormiga 2008), then placed in lactic acid and observed under a Leica DM2500 LED compound microscope. A Leica DMC 4500 digital camera attached to the microscope was used to photograph all the structures illustrated. All measurements are given in millimetres (mm). Males and females were matched based on the following criteria: (1) collected in the same sample, (2) body size, and (3) punctuation pattern and colouration. Morphological nomenclature follows Thoma et al. (2014).  Thoma, 2014: 36-44 Diagnosis. The genus Aposphragisma most resembles the genera Gamasomorpha Karsch, 1881 and Xestaspis Simon, 1884(Thoma et al. 2014) but they can be differentiated based on the combination of the following characters: hard-bodied spiders; sternum with microsculpture; dorsal and ventral abdominal scuta not fused; labium strongly incised; legs without spines. Furthermore, males are distinguished by their palpal bulb bearing an apical embolus closely associated with a laminar conductor (Thoma et al. 2014).

Abbreviations
Distribution. Borneo, Indonesia (Sumatra), Malaysia, Singapore and Vietnam. Etymology. The specific name is an adjective in apposition taken from Latin, meaning globular in reference to the shape of female genitalia.
Diagnosis. Aposphragisma globosum sp. n. males and females can be distinguished from most Aposphragisma species by the presence of prosomal spikes (Fig. 1G) and a coarsely reticulated sternum (Fig. 1F). From A. brunomanseri Thoma, 2014 it can be separated by the presence of only one pair of prosomal spikes (Fig. 1G), the latter species having two pairs of spikes (Thoma et al. 2014;fig. 2E, F); males are differentiated from A. kolleri Thoma, 2014 by their strongly twisted tip of the embolus (Fig. 3B), which is spatulate in the latter species (Thoma et al. 2014; fig. 27C).
Natural History. Specimens were collected in four types of habitats: secondary lowland rainforest, oil palm plantation, and rubber plantation.
Distribution. Known only from the type locality: Harapan on Sumatra. Etymology. The specific name is a noun in apposition and refers to the name of Jambi Province where Bukit Duabelas National Park is located.
Natural History. Specimens were collected in a secondary degraded lowland rainforest only.
Distribution. Known only from the type locality, Bukit Duabelas National Park, Sumatra. Etymology. The specific name is a noun in apposition, the name of the island on which the types were collected.

Aposphragisma sumatra
Diagnosis. Aposphragisma sumatra sp. n. males and females can be distinguished from most of the other Aposphragisma species by their completely reticulate sternum (Fig. 7E, F); from A. confluens Thoma, 2014, A. draconigenum Thoma, 2014, A. nocturnum Thoma, 2014and A. scimitar Thoma, 2014 by their blunt tubercles on the carapace margin (Fig. 7G, H); absent or reduced in the other species; from A. stannum Thoma, 2014 by their longer embolus (Fig. 9B), shorter in the latter species (Thoma et al. 2014; fig. 48D). From A. rimba Thoma, 2014, both males and females are differentiated by their reticulated carapace (Fig. 7G, H) and reduced eyes; in A. rimba the carapace and the eyes are of normal size (Thoma et al. 2014; fig. 38A).
Natural History. Specimens were collected in a secondary degraded lowland rainforest only.
Distribution. Known only from the type locality, Bukit Duabelas National Park, Sumatra.