Three new species of the spider genus Luzonacera Li & Li, 2017 from Philippines (Araneae, Psilodercidae)

Abstract Three new species of Luzonacera Li & Li, 2017 are described: L.francescoballarini Li & Li, sp. n. (♂♀), L.lattuensis Li & Li, sp. n. (♂♀) and L.peterjaegeri Li & Li, sp. n. (♂♀). Prior to this study, the genus was known by two species, both from Luzon Island, Philippines. So far, the genus and all five species are endemic to Luzon Island and can be found in dry or humid caves in a dark environment.


Introduction
The spider family Psilodercidae Machado, 1951 contains eleven genera and 116 species (World Spider Catalog 2018, Li andQuan 2017). All species are restricted to tropical Asia and known from Sri Lanka and India to Philippines (World Spider Catalog 2018). Currently, five species of Psilodercidae belonging to four genera are known to occur in Philippines (World Spider Catalog 2018): Psiloderces egeria Simon, 1892 from Luzon, Althepus noonadanae Brignoli, 1973from Mindanao, Leclercera negros Deeleman-Reinhold, 1995 from Negros, and Luzonacera chang L. duan Li & from Luzon.
The recently described genus Luzonacera  was known from two species, L. chang  and L. duan (World Spider Catalog 2018. While studying new material collected on Luzon Island, we recognized three new species of the genus. The goal of this paper is to provide detailed descriptions of these new species.

Materials and methods
All specimens were collected in Luzon Island and preserved in 95% ethanol solution. All types are deposited in the Institute of Zoology, Chinese Academy of Sciences in Beijing (IZCAS) and Senckenberg Research Institute in Frankfurt (SMF). A Leica M205 C stereomicroscope was used to measure and examine the specimens. Morphological details of the specimens were studied with an Olympus BX41 compound microscope. An Olympus C7070 wide zoom digital camera (7.1 megapixels) mounted on an Olympus SZX12 stereomicroscope was used to take photos. The images were generated using Helicon Focus 6.7.1 image stacking software and further revised with Adobe Photoshop. Leg measurements are shown as total length (femur, patella, tibia, metatarsus, and tarsus). Leg segments were measured from their retrolateral side except for L. peterjaegeri sp. n. which was measured from the prolateral side. All measurements are given in millimetres (mm). Terminology follows that of Li et al. (2014), Tong and Li (2007) and Deeleman-Reinhold (1995).
The extraction of genomic DNA from legs followed Li and Li (2018). Primer sets for the PCR and cycle sequencing reactions used for cytochrome c oxidase subunit I (COI) in this study are from Folmer et al. (1994). All sequences were analysed using BLAST. The GenBank accession numbers are provided in Table 1. The COI dataset of the three sequences obtained in this study and two sequences from Gen-Bank were aligned using MAFFT version 7 (http://mafft.cbrc.jp/ alignment/server/). MEGA7.0.16 (Kumar et al. 2016) was used for subsequent manual adjustment of the sequences and calculation of pairwise comparisons of uncorrected K2P-distances.  -Reinhold, 1995. However, Luzonacera can be differentiated by the combination of the following characteristics: 1) absence of a conductor (versus presence of a conductor in both Althepus and Leclercera); 2) absence of a retrolateral protrusion on the tibia or cymbium of the male palp (versus presence of a retrolateral protrusion on the tibia or cymbium of the male palp in Althepus and Leclercera); 3) remarkably inflated tibia of the male palp; 4) pyriform bulb with spirally extended embolus; and 5) two pairs of spermathecae, the lateral spermathecae with longer stalks than the medial spermathecae.  (the type species), L. duan , L. francescoballarini sp. n., L. lattuensis sp. n. and L. peterjaegeri sp. n.
Illustrated key to the males of Luzonacera 1 Embolus and bulb equal in length; embolus and bulb ratio approximately equal to 1 (Fig. 1i)   Illustrated key to the females of Luzonacera Two pairs of spermathecae pointed almost the same direction (Fig. 2b, d) ..4 -Two pairs of spermathecae pointed opposite directions (Fig. 2c)  Relatively short stalks of medial spermathecae; distal part and stalk ratio approximately 0.5 (Fig. 2d)  Etymology. The species is named after Francesco Ballarin, who collected the type series; name in genitive case.
Diagnosis. Luzonacera francescoballarini sp. n. resembles L. lattuensis sp. n. in having a short embolus, and two pairs of twisted spermathecae globose at distal parts. Males can be distinguished from the latter species by the smooth dorsal surface of the bulb ( Figure 3B); females can be distinguished by having longer spermathecae ( Figure  4A; versus shorter in L. lattuensis sp. n. in Figure 6A).
Distribution. Type locality only ( Figure 10). Natural history. Collected in a dark and rather humid cave, close to the ground, along the wall of the cave with huge rocks.
Comments. Based on the 651 bp aligned sequences, the COI uncorrected K2Pdistance between L. francescoballarini sp. n. and L. chang is 13.5%, between L. francescoballarini sp. n. and L. duan is 15.0%, between L. francescoballarini sp. n. and L. lattuensis sp. n. is 14.9%, and between L. francescoballarini sp. n. and L. peterjaegeri sp. n. is 13.9%.  Etymology. The species name is an adjective referring to the type locality. Diagnosis. Both sexes of L. lattuensis sp. n. and L. francescoballarini sp. n. are very similar. Males of L. lattuensis sp. n. can be distinguished from L. francescoballarini sp. n. by the bulb with a dorsal notch ( Figure 5A) and a relatively longer cymbium tip ( Figure 5E); females can be distinguished by having shorter spermathecae with more widely spaced bases ( Figure 6A; versus longer spermathecae with more narrowly spaced bases in L. francescoballarini sp. n. in Figure 7A).
Distribution. Type locality only ( Figure 10). Natural history. Collected close to the ground along the wall of a dark, rather dry and dusty secondary cave with huge rocks.
Comments. Based on the 651 bp-aligned sequences, the COI uncorrected K2Pdistance between L. lattuensis sp. n. and L. chang is 12.4%, between L. lattuensis sp. n. and L. duan is 11.5%, and between L. lattuensis sp. n. and L. peterjaegeri sp. n. is 13.6%.    Etymology. The species is named after Peter Jäger in honour of his contribution to the study of spiders from Asia; name in genitive case.
Diagnosis. Luzonacera peterjaegeri sp. n. can be distinguished from all other known species of the genus by a distinct constriction on the central part of the bulb ( Figure  7A); females can be distinguished by two types of spermathecae: one pair of slender spermathecae bearing a globose distal part, and one pair of oblique, tube-shaped spermathecae ( Figure 8A; versus both pairs of spermathecae bearing a globose distal part in other species). Moreover, both sexes of L. peterjaegeri sp. n. have longer chelicerae (Figure 8; versus shorter chelicerae in other species).
Description. Male (Holotype). Total length 4.00; carapace 1.50 long, 1.40 wide; abdomen 2.50 long, 1.00 wide. Carapace round, pale brown, with three longitudinal brown bands, with the middle band 3 times wider than the lateral bands ( Figure 8C). Fovea shallow and brown. Anterior margin of thoracic region distinctly elevated. Chelicerae long, brown with lamina, promargin with one tooth, and retromargin with two small teeth ( Figure 9C). Clypeus brown with two pale rounded areas laterally and two relatively longer protrusions basally. Labium brown. Sternum brown with three dark brown patches laterally. Abdomen elongated, with complex patterns  dorsally and ventrally. Leg measurements: all legs missing. Right palp ( Figure 7A-E): tibia swollen at the base, length/width = 2.25; cymbium with distal protrusion, length/width = 3.4; bulb light brown, pyriform; embolus forms a slender spiral elongating terminally from bulb.
Female (paratype). General features and coloration are similar to male, but the female is slightly larger (Figure 8D, E). Measurements: total length 4.17; carapace 1.60 long, 1.28 wide; abdomen 2.56 long, 1.5 wide. Legs missing. Internal genitalia: two pairs of spermathecae, one pair of spermathecae globose distally with long stalks (ca. 6 times longer than distal parts), the other pair are oblique, tube-shaped spermathecae ( Figure 8A).
Distribution. Type locality only ( Figure 10). Comments. Based on the 651 bp aligned sequences, the COI uncorrected K2Pdistance between L. peterjaegeri sp. n. and L. chang is 15.9%, and between L. peterjaegeri sp. n. and L. duan is 13.9%.