Langxie Tang, Jia & Liu, 2023

Tang, Victoria, Jia, Qingquan & Liu, Leonhard, 2023, A new monotypic genus and species from China Langxie feti gen et sp. n. (Scorpiones: Buthidae), Euscorpius 370, pp. 1-101 : 4-10

Langxie Tang, Jia & Liu , gen. n.

( Figures 1–63 , 65 , 82–155 ; Tables 1–3) http: //zoobank. org/urn: lsid: zoobank. org: act: 50719AD2-

C340-417F-A26F-B4D80DE62D88

TYPE SPECIES. Langxie feti sp. n .

ETYMOLOGY. The generic epithet is a noun in apposition, the Pinyin for “ ffiffl ” (láng xiē) in Chinese. Lang (ffi) is the Chinese equivalent for “wolf”, and xie (ffl) is that for “scorpion”. This name is coined for three reasons: (1) the erroneous formal Chinese name for Lychas needs to be replaced ( Tang, 2022a); (2) the new genus was found to be very abundant in the region and exhibited high tolerance to conspecifics, zooming among rock crevices like wolf packs; (3) the new genus was dominant in its habitat, and fed on a variety of prey, including other predatory arthropods.

DIAGNOSIS. Total length ca. 27–38 mm in adult males and ca. 38–45 mm in adult females. General coloration brownish, with whitish yellow pedipalp manus and reddish telson. Pedipalps, metasoma and telson rather slender. Cuticle furnished with prominently developed lattice microstructures. Carapace granular, lacking distinct carinae (except for a pair of posterior median carinae sometimes moderately indicated by granules, but the superciliary carinae constantly appear), flat, isosceles trapezoidal with concave anterior margin. Median eyes very small, situated anteriorly in the ratio ca. 2: 7 to 1: 3. Five pairs of lateral eyes (three major ocelli, two minor ocelli). Tergites I–VI granular, with single median carina, tergite VII with 5 carinae. Sternum type 1, sub-triangular in shape. Pectinal tooth counts 18–21 in males and 16–19 in females. Pectines with conspicuous fulcra. Chelicerae with typical buthid dentition with a single enlarged denticle on ventral side of fixed finger. Metasoma elongate, segment I with 10 carinae, II–IV with 8–10 carinae, lateral median carina can be lacking. Telson elongate, ellipsoidal in shape, with distinct, triangular, subaculear tooth which sometimes presents a secondary tubercle on dorsal surface. Pedipalps orthobothriotaxic, type Aβ, femur trichobothrium d 2 prolateral to prodorsal carina, patella d 3 between retrodorsal and dorsomedian carina. Dentate margin of chela movable finger comprises 6 non-imbricated rows of MDs, row 1 to 5 terminate proximally in a moderately enlarged MD which is flanked by an IAD; apical row anterior to the 1 st row very short, composed of less than 5 subterminal denticles, distal end flanked by one or two terminal denticles; EAD absent from all margins of both fixed and movable fingers. Short tibial spurs present on leg III and leg IV, tibia and tarsus without bristle combs, ventral surfaces of tarsomeres II equipped with 2 rows of short setae (ca. 9–12 for each row), ungues stout.

AFFINITIES. There are eight characters, which in combination differentiate Langxie , gen. n. from all other buthids: pedipalps orthobothriotaxic, type Aβ (beta -configuration); legs III and IV with tibial spurs; pedipalp movable fingers with six non-imbricated rows of denticles; pedipalp movable fingers without EAD; carapace flat; cheliceral fixed finger with a single ventral denticle; telson with a distinct subaculear tooth; metasoma V smooth or granulated without punctate .

The new genus is most similar to both Afrolychas and Lychas in its diagnostic characters. Only two species were included in Afrolychas by Kovařík (2019): A. braueri (Kraepelin, 1896) and A. burdoi (Simon, 1882) . Both species are small-sized and they apparently also differ from the new genus in the following aspects: (1) maculate color pattern; (2) appendages relatively short; (3) metasoma relatively robust; (4) pectines more sexually dimorphic. In A. braueri , the dorsosubmedian carinae of metasoma II–III are armed with prominently enlarged posterior teeth (Kovařík, 2019: figs. 130–133), which is not the case for the new genus. The pectines of A. braueri is obviously sexually dimorphic (Kovařík, 2019: figs. 131, 133), but similar intersexually in L. feti gen. et sp. n. Additionally, the subaculear tubercle of the new genus is either armed with or without a secondary tubercle dorsally. On the other hand, this character is absent in A. burdoi (Kovařík, 2019: fig. 101) and present ventrally in A. braueri (at least visible in females; Kovařík, 2019: figs. 132–133). Due to the scarcity of subordinate taxa, the comparison of the new genus with Afrolychas can be easily biased. The four characters chosen by Kovařík (2019) in his matrix to diagnostically separate the genera may not be sufficient to indicate the phylogenetic relationships between these taxa. Although the new genus shares one more character with Afrolychas , it is hypothesized to be closer to Lychas , but this nonetheless requires a comprehensive phylogenetic study. Biogeographically, the highly disjunct distribution of Afrolychas vs. the new genus, which are isolated from each other by the Himalaya Mountain range, a major vicariant barrier, argues against inclusion of the new species in Afrolychas .

The new genus mainly differs from the Lychas by the loss of all EAD. These regular EADs are present in all the other known species of the “( Ananteris + Isometrus )” clade. Geographically ( Fig. 86 ), the new genus is found most closely to five species of the genus Lychas : L. brehieri ( Myanmar) , L. gravelyi ( Myanmar) , L. mucronatus ( China and Myanmar populations) and L. scutilus ( Myanmar populations). However, both L. brehieri and L. gravelyi were described from Mon State in the south of Myanmar, and the former was discovered in the “Saddan Sin Gu” Cave, while the latter is only known from the Mawlamyine (“Moulmein”), Tenasserim. Moreover, the record of L. scutilus in Myanmar was from Maliwan Village (“ Birma, Malewoon”, No. VA2642, ZMUH), which is further south. As a result, the only closely distributed species of Lychas would be L. mucronatus , with the north-most record from Deqin (Dêqên) County, Diqing Tibetan Autonomous Prefecture (see figure 1 in Tang, 2022b). The Himalaya Mountain system may serve as an effective vicariant barrier blocking gene flow from the Lychas species in India as well. The new genus can be easily distinguished from the geographically close species, L. mucronatus , by a combination of evident characters besides the generic characters: (i) appendages and metasoma much more slender in the new species; (ii) pedipalp chelae do not create prominent gap between cutting edges when closed (in males) in the new species; (iii) coloration much darker, without conspicuous spots throughout the body and immaculate on pedipalp chelae in the new species; (iv) carapace without conspicuous median longitudinal groove posterior to the median ocelli in the new species; (v) carinae on metasoma more developed in the new species; (vi) telson more slender with a slightly less curved aculeus in the new species.

We further compared the new genus with another geographically close buthid genus, Himalayotityobuthus Lourenço, 1997 , which also comprises only two species ( H. martensi Lourenço, 1997 and H. alejandrae Lourenço, 2003 ). The original descriptions for those two species are poor with insufficient illustrations. The new genus clearly differs from Himalayotityobuthus by the presence of pectinal fulcra, and it may be different in other potential aspects (provided that the documentation was correct; Himalayotityobuthus vs. L. feti sp. n.): (1) three lateral ocelli vs. five lateral ocelli (no illustrations); (2) 7–8 vs. 6 rows of denticle (based on the holotype male of H. martensi ; F. Kovařík, pers. comm.); (3) accessory denticles present vs. absent (based on the holotype male of H. martensi ; F. Kovařík, pers. comm.); (4) carapace anteriomedian notch present (e. g., H. martensi ; based on the specimen MNHN-RS-RS8236) vs. absent; (5) spurs strong vs. moderate to weak (qualitative, no illustrations); (6) tarsus with numerous setae vs. two rows of setae comprised of ca. 12 setae (qualitative, no illustrations).

DISTRIBUTION ( Fig. 86 ). China (Tibet Autonomous Region).

COMMENTS

Loss of accessory denticles.

Buthid scorpions are often characterized by their rows of denticles (or granules) on the pedipalp movable finger. Terminologies of these denticles varied in the past literature. Conventionally, the most distal denticle is called a terminal denticle, and those denticles just proximal to it are called subterminal denticles. The short row formed by those subterminal denticles is called an apical row, excluded from the “primary denticle rows”. We identify three types of denticles: internal accessory denticle (IAD), median denticle (MD) and external accessory denticle (EAD). For reference, these have the following notational equivalences in the literature: IAD = gi (granule (accessoire) interne; Vachon, 1950: figs. 72, 74) = ia (inner accessory granules; Stockwell, 1989: fig. 73) = interior lateral granule (Tikader & Bastawade, 1983: fig. 13) = internal series (Pocock, 1990: fig. 3); MD = pg (primary granules; Stockwell, 1989: fig. 73) = grr (granular row; Sissom, 1990: fig. 3.17h) = denticle series (Levy & Amitai, 1980: fig. 8) = median series (Tikader & Bastawade (1983: fig. 13); Pocock (1900: fig. 3)); EAD = ge (granule (accessoire) externe; Vachon, 1950) = oag (outer accessory granule; Levy & Amitai, 1980: fig. 8; Sissom, 1990: figs. 3.17g, i) = external series (Pocock, 1990: fig. 3) = exterior lateral granule (Tikader & Bastawade, 1983: fig. 13) = outer accessory denticle (Levy & Amitai, 1980: fig. 8).. The definition of denticles in Soleglad & Sissom (2001: fig. 1) was different: their “outer denticles (OD)” on their left diagram integrated into the MD series, but separated therefrom on their right diagram. However, their scheme was defined for chactoids and iurids.

All three types of denticles are present in all the previously described species of Afrolychas , Janalychas , Lychas and Spelaeolychas (e. g., Kovařík, 1997: figs. 2–39; Kovařík, 2019: figs. 13–17). The presence of EAD was explicitly confirmed in Kovařík’s (2019) generic diagnosis for all four genera: “… terminated proximally flanked by two enlarged outer accessory denticles …” (in reality, the “two enlarged outer accessory denticles” included one enlarged proximal MD, i. e., only one EAD flanks the denticle rows). The dentition pattern is very similar among all the species: each row of MD is terminated near an IAD distally and an enlarged MD within itself proximally, the latter of which is further flanked by an EAD. The identification and terminology of these denticles were mainly based on position, size and interdenticle spacing. The IAD and EAD always appear alone on the inner and outer margins respectively; usually, the IAD is obviously larger than all MD, while EAD is only slightly larger (if not identical with) than the proximally enlarged MD of each row. MDs of each row are always tightly positioned (contiguous) and the distal MD separates from IAD by a greater spacing. Soleglad & Sissom (2001: 33) wrote: “… corresponding inner and outer denticles are paired for most of the length of the finger, forming denticle group (DG) boundaries within the median denticle row …” in their revision of Euscorpiidae . Therefore, the IAD is conventionally paired with the MD row that is distal to it, i.e., the IAD near the distal end of an MD row is associated with the MD row anterior to this row; hence, the most proximal MD row does not have an IAD. However, the IAD may not always near the distal end of an MD row in buthids. An MD row may terminate distally at the proximal MD of the next distal MD row, and the IAD of the latter may be well separated from it (e. g., in Butheolus Simon, 1882 ; Lowe, 2018: figs. 41–42, 109–110). The most proximal MD of each row is often enlarged and this size increase is gradual from distal to proximal. In some species, the EAD flanks the enlarged MD on the same level or slightly distal to it, and the EAD is often separated by a larger gap than the interdenticle spacing within its adjacent MD row. However, an EAD can be difficult to discern from the MD row if this row is slanted and slightly imbricated. For example, in Barbaracurus Kovařík et al., 2018 , each MD row is non-imbricated, almost linear and terminated by two conspicuously enlarged denticles (i.e., one enlarged MD + one EAD; Kovařík et al., 2018: figs. 1–10). However, in Babycurus Karsch, 1886 , the increase of denticle size is gradual; typically, each row is terminated proximally by three more or less contiguous enlarged denticles (i.e., one enlarged MD + two EADs; Kovařík et al., 2018: figs. 11–23). The consideration of the enlarged MD and two EADs in Babycurus can be potentially defined by the linearity of the MD row. The short “row” comprised of the two EADs forms an obtuse angle against the MD row; the enlarged MD can be regarded as the apex of this angle. In the absence of these two EADs, the MD row is sublinear, which accords with other taxa that show a clear separation between the final MD and EAD, rendering the recognition of MD row feasible (e. g., Kovařík, 2019: fig. 13). However, this depends on how small the angle is (i.e., a larger angle renders the entire MD row plus the EAD(s) more sublinear). A similar consideration is proposed in Tang (2022c) for the identification of the denticle rows of Scorpiops Peters, 1861 .

In our new genus, Langxie gen. n., all EADs are absent from the MD rows. This is a less common condition and so far known only from some “ Buthus group” (sensu Fet et al., 2005; Štundlová et al., 2022) genera and species (e. g., Anomalobuthus Kraepelin, 1900 ( Teruel et al., 2018), Birulatus Vachon, 1974 ( Stathi & Lourenço, 2003), Lissothus Vachon, 1948 (Lourenço & Sadine, 2014), Buthacus arenicola (Simon, 1885) and B. spatzi (Birula, 1911) ( Lourenço, 2006; Cain et al., 2021), a number of species of the “ werneri ” group of Compsobuthus Vachon, 1949 (Levy & Amitai, 1980), and a minority of Orthochirus Karsch, 1891 (as “outer denticles”; e. g., O. formozovi in Kovařík et al., 2020)), as well as in Karasbergia methueni Hewitt, 1913 (belonging to the “( Charmus + Uroplectes ) group”, sensu Štundlová et al., 2022); Hewitt, 1913: pl. XV, fig. 2; Prendini, 2004: 86). The absence of all EADs is unprecedented within Lychas and its three related genera, as well as in other closely related groups (e. g., Isometrus Ehrenberg, 1828 and Reddyanus Vachon, 1972 ; cf. Kovařík et al., 2016: figs. 241–259). The presence of imbricated MD rows and the number of enlarged EAD per row, are considered informative characters for discriminating buthid genera ( Kovařík et al., 2018). The degree of “imbrication” of MD rows is defined by the length of the overlapping (but parallel) region in two adjacent rows (i.e., the posterior region of the anterior row and the anterior region of the posterior row). This can be recognized by how far the final MD of the anterior row extends to the posterior row. Few buthid genera have been considered with imbricated rows: Ananteroides , Babycurus , Buthoscorpio , Centruroides , Egyptobuthus , Grosphus , Heteroctenus , Mesotityus , Odonturus , Tityus and Zabius ( Kovařík et al., 2018) . If the final MD of the anterior row is on the same level with or above the first MD of the posterior row, then the denticle rows are considered non-imbricated. According to the figures in Kovařík (2019: figs. 13–17), the denticle rows of Afrolychas , Janalychas , Lychas and Spelaeolychas are non-imbricated, but there are slight differences: tighter rows (i.e., the final MD of the anterior row is on the same level with the first MD of the posterior row) are sometimes present in Lychas , Janalychas and Spelaeolychas , but never in Afrolychas (i. e., the two MDs are completely separated). In our new genus, each pair of adjacent MD rows are evidently separated by an obvious spacing, and the final MD is further above the IAD of its subordinate row. This renders a rather “loose” arrangement of MD rows. Pseudochactidae is hypothesized to be a basal scorpion family, sister to Buthidae ( Prendini et al., 2021), so it can serve as an outgroup to polarize buthid characters ( Kovařík et al., 2018). All pseudochactids exhibit non-imbricated linear series of MDs with a single EAD; this can be considered as a plesiomorphic state and is shared by many buthid taxa. Therefore, the imbricated rows and multiple EAD may both be derived characters in buthids. All the species in the “( Ananteris + Isometrus ) group” ( Štundlová et al., 2022) previously described also show non-imbricated MD rows and the presence of EAD. Langxie gen. n. apparently belongs to this group in terms of its general characters. However, the loss of all EAD suggests an autapomorphic condition, unique to itself. Phylogenetic relationships can only be analyzed by determining synapomorphies that are shared by more than one species. Hence, the phylogenetic position of this new genus is currently unknown until a more comprehensive study based on DNA sequences and a more detailed morphological character matrix is accomplished.

Figures

Figures 82a–f. Langxie feti gen. et sp. n., in vivo, live paratypes females (82 a, c, d, e) and males (probably subadult, 82b and 82f).

Figures 83a–f. Gula Township, type locality of Langxie feti gen. et sp. n.

Figures 84a–f. Habitat of Langxie feti gen. et sp. n.

Figures 85a–f. Topotypes of Langxie feti gen. et sp. n. observed feeding on different preys in the wild at night.

Figures 86–87: Figure 86. Map showing the representative localities of the discussed species. Langxie feti gen. et sp. n. (★, Gula (Golag) Township, type locality in TibetAutonomous Region, China), Langxie cf. feti gen. et sp. n. (★, Chawalong (Cawarong or Tsawarong) Township, locality in Tibet Autonomous Region, China); Lychas mucronatus (▲, the north-most record in Deqin County of Yunnan Province, China; for other localities, see Tang 2022c); L. brehieri (▲, “Saddan Sin Gu” Cave, type locality in Myanmar); L. gravelyi (▲, Mawlamyine (“Moulmein”), type locality in Myanmar); L. scutilus (▲, Maliwan Village, the only known locality in Myanmar); Afrolychas braueri (■, Praslin Island, type locality in Seychelles); A. burdoi (■, Zanzibar, type locality in Tanzania); Himalayotityobuthus alejandrae (●, north of Saharanpur, type locality in India, approximated from fig. 16 in Lourenço (2003)); H. martensi (●, Tangmarg (left), type locality in India, and locality (“Tribani Ghat”, Lourenço, 1997) in Nepal, approximated from fig. 16 in Lourenço (2003); it appears that “Tribani Ghat” should instead be “Triveni Ghat” (○) in India or “Tribeni” in Nepal (●)). Figures 87a–b: Morphometric analyses of potential sexual dimorphisms among all the adult females and males (one injured adult female excluded; paratype, no. F8). Figure 87a. Bivariate scatter plot comparing ratiometrics regarding pectine length/ metasoma I width (abscissa) vs. pectine length/carapace width (ordinate). Only one pectine of each specimen was examined (the most ideal one, i.e., less deformed). The manual measurement upon these tiny structures can easily arouse errors and deformation of specimens may cause anomalies, thus this result is only referential for the general trend.Figure 87b. Bivariate scatter plot comparing ratiometrics regarding longitudinal diameter of median ocelli/carapace length (abscissa) vs. latitudinal diameter of median ocelli/carapace width (ordinate); normalized in pixels (another female paratype, no. F17 with obvious carapace deformation was excluded).

Figures 88–89: Figures 88a–h: Exemplary procedures of granulometric analysis using ImageJ on a full resolution image of a single carapace. The results of automated computer analysis differ from those obtained by human recognition and delimitation of granule shapes, but are sufficient to resolve sexual dimorphism. Figure 88a. Original carapace image acquired under UV fluorescence. Figure 88b. Carapace surface manually cropped from original image, with brightness and contrast adjusted. Figure 88c. Carapacial margins manually erased to exclude marginal granulation.Figure 88d. Image filtered with a low-pixel Gaussian blur (6-pixel radius) acting as a low-pass filter to suppress digital image noise and minute surface textures (e.g., lattice microstructures) (this step is unnecessary for Fig.91 which already has a lower resolution).Figure 88e. Image filtered again with a higher-pixel Gaussian blur (20-pixel radius), acting as a low pass filter to suppress granules. Figure 88f. Image obtained by subtracting the second filtered image (88e) from the first (88d) to emphasize the granules by removing larger scale background intensity trends; brightness and contrast adjusted.Figure 88g. Result of applying an automatic thresholding algorithm (Yen method).Figure 88h. Particles detected in the thresholded image, under the criteria: area = 7–2,000 pixel2, circularity = 0.50–1.00. Figure 89. Comparison of ROIs retrieved by automatic detection method (left) and manually generated granule profiles estimated by human visual perception and interpretation of the UV fluorescence image (right).

Figure 90. Habitus of all the type specimens of Langxie feti gen. et sp. n.; specimens are placed in the same sequence as the subsequent order of each specimen (start from above to below and left to right (same for all rows of specimens)).

Figure 91. Compilation of carapace morphology of all the types of Langxie feti gen. et sp. n. (first four are juveniles, others are females and last 17 are males).

Figures 1–4: Langxie feti gen. et sp. n., habitus under white light. Figures 1–2. Male holotype in dorsal (1) and ventral (2) views. Figures 3–4. Female paratype in dorsal (3) and ventral (4) views. Scale bar = 10 mm.

Figures 5–6. Langxie feti gen. et sp. n., carapace of female paratype (5) and male holotype (6) under UV light.

Figures 7–8. Langxie feti gen. et sp. n., tergites of female paratype (7) and male holotype (8) and under UV light.

Figures 9–12: Langxie feti gen. et sp. n., coxal and sternopectinal regions (9, 11) and pectines in dorsal aspect (10, 12) under UV light (figures of left and right pectines in dorsal aspect mirrored to directly match the ones in ventral aspect in their above figures). Figures 9–10. Male holotype. Figures 11–12. Female paratype.

Figures 13–14: Langxie feti gen. et sp. n., sternites under UV light. Figure 13. Male holotype. Figure 14. Female paratype.

Figures 15–22: Langxie feti gen. et sp. n., metasoma and telson under UV light. Figures 15–18. Male holotype, metasoma and telson lateral (15), dorsal (16), and ventral (17) and telson lateral (18). Figures 19–22. Female paratype, metasoma and telson lateral (19), dorsal (20), and ventral (21) and telson lateral (22).

Figures 23–26: Langxie feti gen. et sp. n., chelicera in dorsal (23, 25) and ventral (24, 26) views under UV light. Figures 23–24. Male holotype. Figures 25–26(change). Female paratype.

Figures 27–28: Langxie feti gen. et sp. n., pedipalp movable (27a–27b) and fixed (28a–28b) fingers under UV light. Figures 27a–28a. Male holotype. Figures 27b–28b. Female paratype.

Figures 29–46. Langxie feti gen. et sp. n., pedipalp segments of male holotype (29–37) and female paratype (38–46) under UV light. Chela, dorsal (29, 38), external (30, 39) and ventral (31, 40) views. Patella, dorsal (32, 41), external (33, 42) and ventral (34, 43) views. Femur and trochanter, dorsal (35, 44), external (36, 45) and ventral (37, 46) views. The trichobothrial pattern is indicate in Figures 30–33, 35, 39–42, 44 (red circles).

Figures 47–54: Langxie feti gen. et sp. n., right legs I–IV of male holotype (47–50) and female paratype (51–54), retrolateral aspect, under UV light.

Figures 55–57: Langxie feti gen. et sp. n. Figures 55–56. Paratypes female (55) and male (56), sternopectinal areas under white light. Explanation of color markings (55–56): green, distance between left and right basal pectinal teeth; purple, posterior margin of sternite; red, comparison between pectinal tooth length and pectinal lamella width; yellow, boundary between 2nd and 3rd marginal lamellae; dark blue, distance between tip of pectine and trochanter-coxa joint; bright blue, external length of coxa. Figure 57. Paratype female, a single observed case of a dilated (incompletely separated, see red arrow) pectinal tooth.

Figures 58–61: Genital organs of Langxie feti gen. et sp. n. of under white light.Figures 58. Partially damaged hemispermatophores retrieved from an adult male (paratype no. M10). Figure 59. Ovariuterus partially revealed from an adult female (paratype no. F35). Figures 60–61. Removal of genital opercula of an adult male (60) and an adult female (61) paratypes; left genital papilla of the adult male fluoresces under UV light.

Figures 62–63: Langxie feti gen. et sp. n., intraspecific variation. Figure 62. Comparison between the smallest (paratype no. M12) and the largest males (paratype no. M17). Figure 63. Comparison between females (paratypes nos. F31, F40, F18, F4, left to right, and bottom); ovariuterus was not subsequently revealed from the bottom female (F4), and it was then presumed to be immature and its value was not

Figures 64–72. Lattice microstructure comparison among Alayotityus sierramaestrae Armas, 1973 (female, 64; photograph by G. Lowe), Langxie feti gen. et sp. n. (female, paratype, 65), Janalychas tricarinatus (Simon, 1884) (female, 66), Lychas scutilus C. L. Koch, 1845 (juvenile, 67), Lychas mucronatus (Fabricius, 1798) (female, 68, and male, 69), Tityus footei Chamberlin, 1916 (male, 70), Tityus stigmurus (Thorell, 1876) (female, 71) and Tityus smithii Pocock, 1893 (female, 72).