A review of the genus Raveniola (Araneae, Nemesiidae) in China, with notes on allied genera and description of four new species from Yunnan

Abstract The Chinese representatives of Raveniola Zonstein, 1987 are currently recognized to comprise seven species. Four new species – Raveniola montana sp. n. (♂♀), Raveniola shangrila sp. n. (♂), Raveniola songi sp. n. (♂) and Raveniola yunnanensis sp. n. (♂) – are described from the highlands of Yunnan Province, China. According to some characters (shape of the palpus, palpal tibia and tibia I in males) they can be placed together with Raveniola hebeinica Zhu, Zhang & Zhang, 1999 and with Raveniola guangxi (Raven & Schwendinger, 1995), comb. n., transferred here from Sinopesa Raven & Schwendinger, 1995. The current generic position of Raveniola xizangensis (Hu & Li, 1987) is confirmed. Other Chinese nemesiids referred previously to Raveniola are transferred to Sinopesa: Sinopesa chinensis (Kulczyński, 1901), comb. n., Sinopesa sinensis (Zhu & Mao, 1983), comb. n. and Sinopesa chengbuensis (Xu & Yun, 2002), comb. n. The relationships between these Asian genera and their relations to Afrotropical nemesiids are discussed.

introduction Raveniola Zonstein, 1987 with 20 named species is the fifth largest genus of the globally distributed Nemesiidae, encompassing 356 species belonging to 43 genera (Platnick 2012). The genus is restricted to the south Palearctic, chiefly to mountainous regions, and occurs from Turkey to south China. Most species are local endemics and fairly evenly distributed through the range. Raveniola has never been subject to revision. Only two species, R. concolor Zonstein, 2000 andR. vonwicki Zonstein, 2000, were described in the same paper. All other species were described in separate papers using different styles and involving different sets of characters, hindering, if not preventing, identification and proper comparison of species.
Among the countries the highest number of Raveniola species, five out of 20, is reported from China (cf. Platnick 2012). However, this figure can not be considered as high when considering the size of the country and habitat diversity. The much smaller Georgia is inhabited by three species (cf. Mikhailov 1997), while Central Asia, which is comparable in size to China, harbors nine named Raveniola species (cf. Mikhailov 1997;Platnick 2012) and also several undescribed ones (Zonstein, personal data). A recent opportunity to study a little material from south China revealed four undescribed species. To enable description we initiated a review of all nemesiids described or reported from China and compared Raveniola with another genus, Sinopesa Raven & Schwendinger, 1995, occurring in China. The main aims of this paper are thus as follows: to provide 1) a key to all Raveniola species known from China, 2) their diagnoses as well as descriptions of new species, 3) a delimitation of two related genera Raveniola and Sinopesa, and 4) the correct allocation of Chinese nemesiids belonging to these genera.

Material and methods
The study began with an examination of several nemesiid series donated to us by Russian entomologists who had visited Yunnan Province in the People's Republic of China in 2005. One of us (YM), had additionally collected nemesiid material while visited China in 2011. One species (R. hebeinica) was obtained courtesy of our Chinese colleagues (Shuqiang Li and Zhang Feng). A rich collection of comparative material, including the majority of known Raveniola species, as well as representatives of the nemesiid genera Hermacha Simon, 1889, Entypesa Simon, 1902, Lepthercus Purcell, 1902, Pionothele Purcell, 1902, 1, 1 and 3 species, respectively), was obtained from the collections listed below.
Photographs were taken using a Canon 500D digital camera with a 100 mm Canon macro lens and a Zeiss Discovery V20 stereomicroscope with a Canon PowerShot G9 digital camera attached to it. Measurements were taken to an accuracy of 0.01 mm. All measurements are given in millimetres. Total body length includes chelicerae but not spinnerets. Diameter of AME is given usually as a diameter of a sharply edged AME pupil. When the eye dome was mounted well and could be measured, the corresponding data follow in parentheses. Any measurements for this parameter are also given in parentheses. The length of sternum was measured along the straight line between the posterior tip of the sternum and the hindmost part of the labium. Lengths of leg and palp segments were measured on the dorsal side, and lengths of spinneret segments on the ventral side, from midpoint of anterior margin to midpoint of posterior margin. Lengths of palps and legs are given as: total (femur, patella, tibia, metatarsus and tarsus). Fig. 1 was created on the base of a small tourist map located online at http://www. homepages.ucl.ac.uk/~zczcc07/maps.htm and claimed to be free to reproduce and use. taxonomy Distribution, habitats and ecology. Over 20 species are currently known in the south Palearctic, from Turkey to China (see Platnick 2012). The spiders inhabit different types of forest and steppe biotopes, subalpine and alpine meadows from seashore up to 4300 m above sea level. They can occur under rocks and logs, or inhabit abandoned rodent burrows, or crevices. Adult females can be found building simple burrows 10-20 cm (in R. ferghanensis -up to 40-50 cm) depth with weak silk lining and open entrance.
Unfortunately, we have no direct label data shoving peculiarities in the habitats and ecology of Chinese species of Raveniola. The only male of R. yunnanensis sp. n. was found under the rock in the mixed mountainous broad-leaved forest (I. Kabak, personal communication). The representatives of R. montana sp. n., R. shangrila sp. n. and R. songi sp. n. were collected with pitfall traps together with highland ants Myrmica pleiorhytida Radchenko & Elmes, 2009 (Hymenoptera, Formicidae) by the same collectors and in the same biotope. The latter species was noted inhabiting mountainous meadows (see Radchenko & Elmes 2010, p. 219).
Distribution. Known only from the type locality ( Fig. 1). Diagnosis. The species differs from all known Chinese Raveniola species by small lateral receptacles in females (cf. Zhu et al. 1999, fig. 7) and by the subapically curved embolus in males (cf. Zhu et al. 1999, figs 8-10).

Raveniola hebeinica
Description. ♂♀ were well described by Zhu et al. (1999). Male carapace, sternum with labium and maxillae, tibia and metatarsus I, palpal tibia and cymbium, bulbus and female spermathecae as shown in Figs 8,16,25,31,39 and 47,respectively. Variability. The only examined male has carapace 7.02 mm long (7.29 in the holotype). The carapace of the noticeably smaller examined adult female measures only 5.17 mm (vs. 6.67 in the female paratype used at the description).
Distribution. CHINA: Hebei Province and Beijing Municipality (Fig. 1). Etymology. The specific epithet montana is derived from the Latin montanus (pertaining to the mountains), referring to the mountain habitat of this species.

Raveniola montana
Diagnosis. The species differs from all other Chinese species of Raveniola by having a short embolus provided with deep ridges in males (Fig. 40); the specific configuration of female spermathecae is shown in Fig. 48.
Description. Male (holotype). Body length 15.50. Colour in alcohol: carapace, chelicerae, palps and first pair of legs dorsally intense reddish brown; eye tubercle with darker spots surrounding AMEs and lateral eyes; sternum, labium, maxillae and legs II-IV light reddish brown; dorsal abdomen uniformly light greyish brown, ventral abdominal surface and spinnerets pale greyish brown.
Distribution. CHINA: Yunnan Province (Fig. 1). Etymology. The specific epithet is given in honour of the mythical Tibetan land Shangri-La attributed to the highland region located in the far eastern part of Tibet (Xizang) and north-western part of Yunnan, i.e., including the type locality of this species.

Raveniola shangrila
Diagnosis. The full reduction of PMS allows to place this species together with R. guangxi; R. shangrila can be distinguished from the latter species by shape of the embolus and larger number of maxillary cuspules -15-20 vs. [3][4]30,37 and 19,33,41,respectively). In general, specimens of Raveniola shangrila sp. n. appear poorly distinguishable from those of R. songi sp. n., but certain distinctions in the configuration of male bulb and metatarsus I are evident (cf. Figs 15, 16, 23 and 24).
Female unknown. Variability. Carapace length in males varies from 5.03 to 5.95 (n=5). Distribution. CHINA: Yunnan Province (Fig. 1). Etymology. The specific name is given in honour and memory of Prof. Daxiang Song (宋大祥;1935-2008, for his immense contribution to Chinese arachnological research.
Female unknown. Variability. Carapace length in males varies from 4.80 to 5.43 (n=12). Distribution. CHINA: Yunnan Province (Fig. 1). Etymology. The specific epithet is given after the name of the inhabited region (Yunnan).

Raveniola yunnanensis
Diagnosis. Males differ from all other Chinese congeners by lighter body colouration and longer legs (tibia I 5.5 times as longer than wide vs. 4-5 times in other species) and more spinose embolus armed with ca. 25-30 spines (vs. 3-7).
Scopula: moderately dense and long -entire covering whole ventral metatarsus I and distal 2/3 of metatarsus II, entire on tarsi I-II, divided by setae on tarsus III; widely divided and vestigial on metatarsus III and tarsus IV. Paired claws: legs I-III with 6-8 teeth, leg IV with 9 teeth in two rows on each claw. Trichobothria: 2 rows of 6-8 per row on tibiae, 10-12 on metatarsi, 8-10 on tarsi, 6 on cymbium.
Description. This largest Chinese nemesiid with carapace 11-12 mm long was well described by Hu and Li (1987). Bulbus and spermathecae as shown in Figs 49 and 50.

Discussion
Three nemesiid genera have been reported from China to date. The first is Nemesia Audouin, 1826, represented here by the enigmatic N. sinensis, known only from the holotype female (Pocock 1901). Judging from the description, this species possesses, unlike most nemesiids, spinose leg tarsi and sparcely spinose leg IV and thus might actually belong to the Cyrtaucheniidae. In addition, all correctly described Nemesia are known westwardly the Caucasus. The second genus is Raveniola, which, according to the Chinese authors (Song et al. 1999;Xu and Yin 2002), includes the majority of the regional nemesiids sharing the diagnostic characters indicated by : the sequential retroventral megaspines in males and divided spermathecae in females. Finally, at least one Chinese nemesiid was referred to the endemic East-Asian genus Sinopesa (see Raven and Schwendinger 1995).
While establishing Sinopesa, Raven and Schwendinger separated it from the related genus Entypesa on the basis of two characters: the absence of PMS and of serrula. The apical segment of PLS in Sinopesa spp. was found to be digitiform. Later, Shimojana and Haupt (2000) described S. kumensis from Ryuku islands, Japan, as definitely related to the type species S. maculata Raven & Schwendinger, 1995, but possessing PMS though in the reduced form. One more unequivocal character of Sinopesa that has not been specially noted by the above-mentioned authors is a retroventral position of male megaspines; also shared by some other nemesiids: by the African genera Entypesa (Figs  3, 22), Lepthercus and Pionothele (whereas in the definitely related Hermacha the male tibia I appears to be unmodified) and, as just stated, by Raveniola. At least for the latter genus, the very construction was shown to be connected with the specific way of the female fixation during the mating (Zonstein 2002).
It should be noted that in the mentioned African genera the spinneret morphology retains the more plesiomorphic condition: PMS are relatively large and fully functional, and the apical segment of PLS in all these genera except Pionothele is long and slender (digitiform). The spinneret morphology in Sinopesa is noted above. In Raveniola species PMS are small to tiny; within the species described to date they are absent in R. fedotovi (Charitonov, 1946) and R. kopetdaghensis (Fet, 1984); the apical segment of PLS varies, with few exceptions (see Zonstein 2009), from short-digitiform to triangular.
Although Sinopesa and Raveniola have never hitherto been compared to one another, they share a number of apomorphies that might bring them closer to each other than to the mentioned genera. Some of these characters, such as the absence of the maxillary serrula and the metatarsal preening combs, are also shared with Lepthercus and Pionothele; whereas other features appear to be unique. Males of both Asian nemesiid genera share the presence of 2-3 (vs. one in the mentioned African nemesiids, as shown in Fig. 22) retroventral megaspines on tibia I. The congeneric females possess the divided spermathecae (that are entire in Entypesa and Hermacha -see Raven 1985; for Lepthercus and Pionothele known from males this character is uncertain). The most important shared feature is that within the Mygalomorphae only males of Raveniola and Sinopesa are found to possess the intercheliceral tumescence located ventrally (not prolaterally) and confined to the cheliceral furrow.
Differences between Chinese members of Sinopesa and Raveniola are summarised below: In the course of this study the characters of three Chinese nemesiids previously placed in Raveniola were found to correspond to the diagnostic features of Sinopesa. Hence, they are transferred here to the latter genus: S. chinensis (Kulczyński, 1901) comb. n., S. sinensis (Zhu & Mao, 1983) comb. n. and S. chengbuensis (Xu & Yun, 2002) comb. n. Moreover, using the same definitive criteria, one of the existing members of Sinopesa should be transferred to Raveniola: R. guangxi (Raven & Schwendinger, 1995) comb. n. The current generic position of R. xizangensis (Hu & Li, 1987) and R. hebeinica Zhu et al., 1999, whose features do not contradict the generic characters, is presently confirmed.
Being compared by shape of the male embolus and female spermathecae with other Raveniola species, the Chinese representatives showed a closer similarity to the Central Asian congeners and especially to North-West Himalayan R. concolor (cf. Zonstein 2000, figs 4-6), as well as it was possible to expect.

Prospective
Seven true Chinese species of Raveniola were revealed in course of this study, which engages here, however, only with the material and information previously available. Currently, we cannot estimate the true diversity of Raveniola species within the country, but expect it to be much higher. This expectation is based, first and foremost, on the fact that many parts of the region were not specially investigated; while a rather small amount of material from two geographically close localities has already revealed four new species. An additional possible factor relates to the limited and often sympatric character of their distribution, specific to this group of spiders. Numerous mountain ridges in central and southern parts of China (which provide both the mosaic character and richness of habitats) and lack of special collection efforts suitable for these mygalomorphs, reinforces the prediction regarding their probably higher species diversity.
The prospective areas in which new findings might be expected are the provinces lying between the two main groups of the known localities (see Fig. 1), especially Sichuan and southern part of Gansu. It should be noted that the members of this genus may also occur in the furthest north-western part of China. According to our data (Zonstein, in prep.), some Raveniola species were observed in Kyrgyzstan, inhabiting Alai and Trans-Alai Mt. Ridges, both adjoining Xingjian.