The new Southeast Asian genus Cambonilla gen. nov. (Zodariidae, Araneae): ‘bis repetita placent’

The new genus Cambonilla Jocqué gen. nov. is described on the base of two species, each known from both sexes. A cladistic analysis based on morphology, showed that the new genus is the sister-group of Heliconilla Dankittipakul, Jocqué & Singtripop, 2012 with which it shares the granulated carapace with branched setae and the marbled ventral abdominal pattern, but differs by the abdominal, tubular sclerotized protrusion around the pedicel in males and the absence of posterior ventral abdominal spines in the female. The type species Cambonilla securicula Jocqué gen. et sp. nov. was found in rainforest along the Mekong River in Cambodia and Laos. The second species Cambonilla symphonia Jocqué & Henrard gen. et sp. nov., provided with conspicuous femoral stridulating organs, was recorded from the same localities but in Cambodia only. An illustrated key to the genera of tropical Asia is presented.


Introduction
The genus Mallinella Strand, 1906 is with more than 200 species known and many more to be described, by far the largest genus in the Zodariidae (Jocqué 1991;Nzigidahera et al. 2011). In a review of the genus from East Asia, Dankittipakul et al. (2012) described two genera closely related to Mallinella: Workmania Singtripop, 2012 andHeliconilla Dankittipakul, Jocqué &Singtripop, 2012. The latter turned out to be the sister-group of Mallinella in an analysis based on 98 morphological characters (Dankittipakul et al. 2012). During a recent inventory in lowland forest in Cambodia, two species were found that appear to belong to yet another unknown genus, hence the subtitle of the paper: 'bis repetita placent' (nice to have it twice!). Not only because this is the second paper describing new taxa on the generic level in this clade, but also because two species are involved which supports the 'new genus' hypothesis. Considering the fact that the forest soil spider fauna of the country is very poorly known, Asceua septemmaculata (Simon, 1893) is the only species of zodariids that has been recorded from there (World Spider Catalog 2018), it is not surprising to fi nd novelties in the area, even at the genus level. Apart from the species of the new genus, the collection further contained two species of Asceua Thorell, 1887, three of Mallinella, one of Storenomorpha Simon, 1884 and one of Tropizodium Jocqué & Churchill, 2005. We here describe the new genus, provide a cladistic analysis to illustrate its relationships and present a new key to the genera of tropical Asia.

Material and methods
Specimens were observed, drawn and measured with a WILD M 10 stereo microscope. Measurements and photographs of the habitus, details of body parts, detached male palps and female genitalia were taken with a Leica MZ16 using the LAS automontage software (ver. 3.8). The female genitalia were dissected and digested with pancreatin, then immersed in 75% ethanol.
For SEM photographs, specimens were dried overnight in Hexamethyldisilazane, gold coated and examined and photographed with a JEOL 6480 LV scanning electron microscope. All types are deposited in the Royal Belgian Institute of Natural Sciences (RBINS Brussels, Belgium) and vouchers in the Naturmuseum Senckenberg (SMF, Frankfurt, Germany). All measurements are in mm. All palp illustrations are from left palps except the ventral view with SEM. Maps were created with the online tool SimpleMappr (Shorthouse 2010

Phylogenetic analysis
The analysis is based upon the data matrix used by Dankittipakul et al. (2012). We used the same outgroups Storenomorpha reinholdae Jocqué & Bosmans, 1989 and Cydrela pristina Dankittipakul & Jocqué, 2004but also Asceua dispar (Kulczynski, 1911 with the same scoring as Asceua sp. it replaces. Including these, we made a selection of 44 species, out of the original 84, plus the two new species described in this paper. The selection contained representatives of the different species-groups of Mallinella Strand, 1906, of Heradion Dankittipakul & Jocqué, 2004, Euryeidon Dankittipakul & Jocqué, 2004, Workmania Dankittipakul et al., 2012 and eight out of the ten known Heliconilla Dankittipakul et al., 2012. The same 98 characters were used. Only two characters were added and for character 22 concerning the presence of PVS, the specifi cation 'in males' was added. The new characters are: 99. Female palpal tibia 0. without sinuous modifi ed spine; 1. with short, sinuous modifi ed spine (although uninformative, only one species in the matrix shows this character, it was considered special enough to have a trace of it in the matrix).
100. PVS on abdomen in females. 0. absent; 1. in single row; 2. in more than one row or a group. The score was identical as that of character 22 (now restricted to males), except for Cambonilla Jocqué gen. nov. because there are no PVS in the females.
The scoring for the new species is as follows: Analyses were carried out with Winclada (version 1.00. 08 Nixon 199908 Nixon -2002 by using 'the ratchet' with default settings (200 iterations, 1 tree to be hold, 9 characters to sample). Twelve characters were uninformative, including the new 99, and were deactivated.

Results
The parsimony analysis in Winclada resulted in fi ve equally long trees with length 415 , consistency index 45 and retention index 72. The preferred tree is shown in Fig. 1. In three of the fi ve trees, and evidently also in the majority consensus (60%), Cambonilla gen. nov. and Heliconilla turned out to be sister-groups, forming a clade, which is sister to Mallinella including Workmania. In the other two, 13. Chelicerae with two small teeth on promargin; PLE more than three times their diameter from PME (Y); AER strongly pro-curved; carapace strongly domed and strongly granulated; dorsal scutum on opisthosoma large and ovoid, heavily sclerotized .

Diagnosis
Species of Cambonilla gen. nov. are recognized by the tubular protrusion around the pedicel and dispersed PVS, with rows of tiny denticles in males, absence of PVS in females; both sexes have a marbled pattern of the abdominal venter, strongly recurved PER and granulate carapace teguments.

Etymology
The genus name is derived from the country of the type locality Cambodia, in combination with the ending of its sister genus Heliconilla. The gender is feminine.

Description
MEDIUM SIZE SPIDERS (7.5-7.3 mm). With granulate teguments of carapace ( Fig. 2A), sternum and basal leg segments. Carapace longer than wide (L/W < 1.29-1.65) with sparse cover of split pale setae (Fig. 2B); widest at level of coxae II, narrowed to about 0.63 times maximum width in males ( Carapace dark brown; chelicerae, legs, mouthparts and sternum medium to orange brown; abdomen dorsum dark with pattern of numerous white spots without apodemes, in males anteriorly overlaid by transparent reddish orange oval scutum; venter with sepia pattern on dark background; sclerotized in front of epigastric fold, in males extended into short tubular extension around pedicel. EYES. In two strongly procurved rows: PLE at level of AME (Fig. 2D). All eyes pale and subequal. Clypeus straight, height 2.8 to 4.2 times diameter of ALE (Figs 2D, 5C).
CHILUM. Single, well developed and delimited, protruding in the middle. Chelicerae conical with many evenly dispersed setae; without teeth; fangs about three times longer than wide at base (Fig. 2E). Labium triangular. Endites roughly triangular, converging (Fig. 5B). Sternum shield-shaped, almost as wide as long, with rounded precoxal depressions ( Fig. 4A-B); anterior margin straight, lateral margins with inter-and intracoxal triangular extensions; posterior tip slightly indented in males, rounded or truncate in females.
LEGS. Slender. Formula 4123 or 4132. Tibial process well developed in all legs. Spination reduced on legs I and II, well developed on III and IV. Most spines short and slender. Bothria with three ridges (Fig. 1F). Superior tarsal claws with up to 15 teeth on leg I and II (Fig. 3A), with up to 8 teeth on legs III and IV (Fig. 3B). One dorsal hinged hair on tibiae I and II (Fig. 3C). Mt II-IV with preening brush of chisel-shaped setae (Fig. 3D). FEMALE PALPAL TARSUS. With claw turned inward over ± 30°, provided with four or fi ve small, basal, prolateral teeth; with several spines; without distal patch of chemosensitive setae.
ABDOMEN. Oval; tracheal spiracle fairly small, provided with small rectangular scutellum. Both sexes with six spinnerets. ALS large, conical, biarticulate. PLS and PMS provided with 1 and 4 cylindrical gland spigots respectively. Colulus represented by haired fi eld. Venter with dispersed thick setae in posterior half (Figs 5B, D, 8B, D) and with short PVS provided with rows of tiny denticles (Fig. 3E-F), in ill-defi ned row and/or group in males; both absent in females; hinged hairs sparse ( Fig. 6B-C).

Diagnosis
The male of Cambonilla securicula sp. nov. is recognized by the presence of small lateral scuta behind the epigastric fold and by the male palp in which both the MA and the C are hatchet shaped. The female has a remarkable, small, modifi ed spine on the tibia of the palp and a characteristic epigyne in which the central plate has a concave anterior and a straight posterior margin.

Etymology
The species name 'securicula' meaning hatchet, is a noun in apposition referring to the shape of both the MA and the C.

Description
Male holotype TOTAL LENGTH. 6.96. Carapace: length 3.48, width 2.70, height 2.00. COLOUR (Fig. 5A-D). Carapace uniform dark chestnut brown; chelicerae dark brown with orange extremity and white tip; chilum medium brown; sternum medium brown; labium and endites medium brown, paler towards anterior white tip; legs: Cx and Tr medium brown, Fe dark brown, P and T greyish brown, Mt and t pale brown. Abdomen: dorsum with pale reniform patches fused in front and at posterior end, overlaid by reddish orange, translucent oval scutum; further backward with fi ve transverse bands and pale patch above spinnerets on dark background; venter sclerotized in front of epigastric furrow and yellow sclerotized area on either side behind epigastric furrow; remainder marbled with sepia on pale background; spinnerets pale brown. CARAPACE GRANULATED. With sparse cover of thin, pale, branched setae.
MALE PALP (Figs 4C-F, 5E-F, 7A-B). T with strong, slightly sinuous, downcurved, blunt RTA; cymbial fold as long as half the cymbium's length; embolus with large base, originating at an angle of 270° to longitudinal axis, halfway with short, fl at bifurcation, distal end corkscrew shaped; MA hatchet-shaped with short ventral tooth at base; C with short, sharp, fl at, distal protrusion, pointing prolaterad.   (Fig. 6A-C). Carapace uniform dark brown; chelicerae medium brown with pale tip; chilum medium brown. Endites and labium medium brown with pale frontal margin. Sternum uniform medium brown. Legs I: Cx medium brown, Tr pale brown, F dark brown, remainder yellowish orange; palp medium brown except T yellowish orange. Abdomen: dorsum with two ill-defi ned reniform spots touching in front, without scutum overlay, followed by small, faint, pale patches and large patch in front of spinnerets; venter with sclerotized band in front of epigastric furrow, without tubular extension, remainder marbled with sepia on pale background, spinnerets pale yellow.
CARAPACE. Rugose with sparse cover of branched setae.
EPIGYNE (Figs 6D-E, 9D). With wide rectangular plate, concave in front, posterior margin convex and thickened in the middle. Copulatory ducts with few whorls, ending in poorly delimited spermathecae near posterior end.

Variation
The abdominal venter of the female specimen from Ban Tathot (17.62361 °N, 105.1466 °E) is not marbled but has three dark, faint longitudinal lines.

Distribution
Known from lowland forest in Cambodia and Laos; all localities are along the Mekong river (Fig. 11).

Etymology
The species name 'symphonia' is a noun in apposition meaning 'orchestra' and refers to the four stridulating organs on the femora of the male.  Fig. 8A-D). Carapace uniform chestnut brown; chelicerae, chilum and sternum brownish orange; endites and labium pale brown with whitish distal margin; legs: Cx and Tr pale brown; Fe dark brown; remainder yellow except T IV medium greyish brown; abdomen: dorsum with two reniform pale patches in front overlaid by translucent pale reddish brown, oval scutum followed by numerous small white spots on dark background, venter sclerotized orange in front of epigastric furrow with short tubular extension around pedicel; remainder with sepia marbling on pale background; spinnerets whitish; sides with dark grey marbling.
LEGS. Trochanters III and IV with anterior ventral indentation; Fe I and II with basal dorsal stridulation fi le (Fig. 4G-H)  ABDOMEN. Venter with dispersed thick setae in posterior half (Fig. 8D); with short tubular extension around pedicel, ventral margin slightly indented (Fig. 8A-B). (Figs 8E-F, 10A-B). T with a strong, straight, tapered RTA and retrobasal triangular swelling; cymbial fold slightly shorter than half the cymbium's length; embolus with large base, originating at an angle of 270° to longitudinal axis; bifi d from base onwards; MA with basal tooth and beak shaped distal extremity pointing prolaterad; C short, tapered, grooved.

MALE PALP
Female (RBINS IG 33.889/008) TOTAL LENGTH. 6.60. Carapace: length 2.56, width 1.56, height 1.14. COLOUR ( Fig. 9A-C). Carapace uniform dark brown; chelicerae medium brown without pale tip; chilum medium brown. Endites and labium medium brown with pale frontal margin. Sternum uniform medium brown. Legs: Cx yellowish brown, with white sital margin; Tr yellowish brown, F dark brown, remainder medium brown; palp medium brown, F slightly darker. Abdomen: dorsum anteriorly with two well separated reniform spots, without scutum overlay, followed by pale transverse band, small, pale patches and large patch in front of spinnerets; venter with sclerotized band in front of epigastric furrow, remainder with sepia marbling on pale background, spinnerets yellow.
CARAPACE. Rugose, with sparse, thin, pale, branched setae; a few large setae between eye region and fovea.

Distribution
Known from two localities along the Mekong River in Cambodia (Fig. 11).

Discussion
The discovery of a new genus in the large clade containing Mallinella is not particularly surprising mainly because it comes from an area that has hardly been surveyed for spiders (see introduction). It is remarkable though, that the type species has a very vast distribution, which appears to be linked with rainforest along the Mekong River. The adjacent regions in Thailand have been well inventoried (Dankittipakul et al. 2012) and the taxon is most likely absent from there. As far as we know, this is the fi rst case of a riverine forest distribution in the Zodariidae.
Cambonilla gen. nov. appears more closely related to Heliconilla than to the other genera in the group and is easily recognized as such by the marbled venter of the abdomen, which they share, together with several other characters. However, one of the specimens of C. securicula gen. et sp. nov. has an abdominal ventral pattern that is aberrant in this respect (see variation above): it has three longitudinal faint dark lines on a pale background, a pattern that is common in species of Mallinella. This suggests that some of the characters in this group might be the result of epigenetic gene expression, a phenomenon that has been recognized as a source of variation in phenotypes (Vogt 2015;Gawne et al. 2018). Even at the species level, characters may pop up at several places in a clade: this is the case for femoral stridulating orga ns in our ingroup: they are present in Cambonilla symphonia gen. et sp. nov., in Mallinella annulipes (Thorell, 1892) (see Jocqué 2005) and in several species of Euryeidon (e. g. Euryeidon musicum Dankittipakul & Jocqué, 2004) (Dankittipakul & Jocqué 2004). This phenomenon evidently puts the value of a purely morphological analysis in perspective, but it would be surprising if a molecular analysis contradicts the hypothesis that the Cambonilla gen. nov. species represent a separate genus, considering the number of characters that defi ne it on the preferred tree (Fig. 1).