Vietbocap canhi Lourenço and Pham, 2010

Prendini, Lorenzo, Ehrenthal, Valentin L. & Loria, Stephanie F., 2021, Systematics Of The Relictual Asian Scorpion Family Pseudochactidae Gromov, 1998, With A Review Of Cavernicolous, Troglobitic, And Troglomorphic Scorpions, Bulletin of the American Museum of Natural History 2021 (453), pp. 1-153 : 100-107

Vietbocap canhi Lourenço and Pham, 2010

Figures 4A, E, 5, 7–9, 12B, D, F, 14B, D, F, 15D, 17D, E, 19D, E, 21D, E, 40–43, tables 1–5, 10

Scorpionida sp. nov.: Moulds et al., 2010: 4–6, 17, 18, 20, 34, fig. 3.3, table 1.

Vietbocap canhi Lourenço and Pham, 2010: 7–12 , figs. 3–24; Fet et al., 2011a: 15; Lourenço, 2012a: 233, 235–237, fig. 3G, appendix A; 2012b: 733, table 1; Lourenço and Leguin, 2012: 71; Lourenço and Pham, 2012: 81–84, fig. 3B, E, H; Soleglad et al., 2012: 89; Moulds et al., 2013: 14; Loria and Prendini, 2014: 3, table 1; Lourenço, 2014: 31; Beron, 2015: 184; Pham et al., 2017: 134, 135, fig. 1; Beron, 2018: 834; Lourenço et al., 2018: 265; Francke, 2019: 32.

Vietbocap thienduongensis Lourenço and Pham, 2012: 82–85 , fig. 3A, C, D, F, G; Lourenço, 2012a: 236, 237, appendix A; 2012b: 732, 733, table 1, fig. 2; Lourenço and Leguin, 2012: 71; Soleglad et al., 2012: 89; Moulds

et al., 2013: 14; Loria and Prendini, 2014: 3, table 1; Lourenço, 2014: 31, 37, fig. 6; Pham et al., 2017: 134, 136, figs. 1, 4; Beron, 2018: 834; Lourenço, 2018: 2, fig. 2; Lourenço et al., 2018: 264–267, 269, 271; syn. nov.

Vietbocap aurantiacus Lourenço et al., 2018: 268 , 269, 271, figs. 6, 7; syn. nov.

Vietbocap quinquemilia Lourenço et al., 2018: 269–271 , figs. 8–11; syn. nov.

TYPE MATERIAL: VIETNAM: Qu ảng Bình Prov.: Bố Trạch Distr. : Phong Nha-Kẻ Bàng National Park: Holotype: 1 [juv.] ♂ ( MNHN RS 8850), paratypes: 1 [juv.] ♀ ( MNHN RS 8851), 2 [juv.] ♀ ( IEBR), Tiên SƠn cave, 17°32′N 106°16′E, 16.v.2010, D.-S. Pham, mid section of the cave (200 m from cave entrance), No. VNS-01. Vietbocap thienduongensis : Holotype [subad.] ♂ ( MNHH), paratype [juv.] ♂ ( IEBR), Thiên ĐƯ ờng cave, mid section of cave (1800 m from cave entrance), 9.viii.2011, N.K. Dang. Vietbocap aurantiacus : Holotype ♀, paratype [juv.] ♀ ( MNHN), paratype [juv.] ♀ ( IEBR), Thiên ĐƯ ờng cave (17°31′10.3″N 106°13′22.9″E), midsection of cave (3000 m from cave entrance), 23.v.2013, D.-S. Pham. Vietbocap quinquemilia : Holotype: [juv.] ♂, paratype: [juv.] ♀ ( MNHN), paratype ♀ ( IEBR), Thiên ĐƯ ờng cave (17°31′10.3″N 106°13′22.9″E), midsection of cave (5000 m from cave entrance), 6.iv.2015, D.-S. Pham. It is apparent from the measurements and illustrations provided in the descriptions ( Lourenço and Pham, 2010, 2012; Lourenço et al., 2018) that all except the holotype of V. aurantiacus are immature.

DIAGNOSIS: As for genus.

DESCRIPTION: The following description, based on the material examined, which includes eight adult females, supplements the descriptions of Lourenço and Pham (2010, 2012) and Lourenço et al. (2018). It is unclear from the published photographs and measurements whether any of the males collected thus far are adult (no adult males were examined in the present study). Based on size and coloration, the holotypes of V. canhi and V. quinquemilia are immature, whereas the holotype of V. thienduongensis appears to be subadult. Ratios are presented for adult females only (tables 3, 10) whereas counts include immatures of both sexes (tables 3–5, 10).

Total length: Small, 31 mm (27.2–35.8 mm, n = 9) (tables 3, 10).

Color: Tegument base coloration pale yellowish to reddish yellow (whitish in immatures), immaculate. Chelicerae, pedipalps (except chela fingers), legs, posterior third of tergites and sternites, and telson slightly paler than carapace, pedipalp chela fingers, anterior two-thirds of tergites and sternites, and metasoma. Chela fingers dark reddish; pedipalpal and metasomal carinae reddish. Sternum, genital operculum, pectines, and sternites pale, whitish. Aculeus reddish black.

Chelicerae: Fixed finger, dorsal margin with four teeth (basal, median, subdistal, distal); basal and median teeth fused into bicuspid (“conjoined on trunk”); space between median and subdistal teeth U-shaped; ventral margin with three to five very small denticles (ventral accessory denticles). Movable finger, dorsal margin with three teeth (median, subdistal, retrolateral distal), without basal teeth; ventral margin with four or five very small denticles (ventral accessory denticles) and serrula in distal third; retrolateral (dorsal) distal and prolateral (ventral) distal teeth subequal, retrolateral (dorsal) distal tooth smaller than prolateral (ventral) distal tooth, and opposable. Ventral surface of fingers and manus with numerous long, dense macrosetae.

Carapace: Carapace slightly wider than long, anterior width 52% (47%–60%, n = 9) of length, length 101% (90%–107%, n = 9) of posterior width (tables 3, 10). Anterior margin protruding but shallowly concave (recurved) medially; anterolateral margins with pronounced rostrolateral incisions, lateral to lateral ocelli; posteromedian margin shallowly concave (recurved); posterolateral margins gently curved (fig. 12B, D, F). Median and lateral ocelli absent. Anterosubmedial depressions, medial to lateral ocelli, well developed. Median ocular tubercle represented by smooth, flat to slightly depressed surface, situated approximately medially on carapace, distance from anterior margin 46% (44%–47%, n = 8) of carapace length (table 10); superciliary carinae absent; interocular sulcus obsolete, shallow to deep. Circumocular sutures partial (discon- nected); circumocular triangle parallel sided (U-shape), median ocular curvatures (regardless of absence of median ocelli) absent. Anteromedian depression narrow, deep; posteromedian sulcus shallow anteriorly, becoming deeper posteriorly; posterolateral sulci very shallow, wide, weakly curved; posteromarginal sulcus narrow, shallow. Carapace surfaces entirely smooth, except near anterior margin, and acarinate.

Pedipalps: Pedipalps gracile; segments apilose. Pedipalp femur width 80% (78%–82%, n = 9) greater than length (tables 3, 10). Femur with five carinae evident (fig. 42A–D); promedian carina vestigial, reduced to few proximal spiniform granules; dorsomedian, prodorsal and proventral carinae weakly developed, granular; retrodorsal carina obsolete, reduced to few granules; retromedian, retroventral, and ventromedian carinae absent; intercarinal surfaces smooth. Pedipalp patella length 71% (70%–72%, n = 9) greater than width (tables 3, 10). Patella with six carinae evident (fig. 42E–H); prodorsal, retrodorsal, proventral, and retroventral carinae weak, granular; prolateral surface, dorsoventral “vaulted” projection (“anterior process”) moderately developed, with prominent pair of dorsal and ventral spiniform granules (“patellar spurs”) proximally, demarcating pair of obsolete, granular prolateral carinae (“dorsal and ventral patellar spur carinae”); dorsomedian, retromedian, and ventromedian carinae absent; intercarinal surfaces smooth. Pedipalp chela relatively short and broad; manus elongate, width 97% (87%–106%, n = 9) of height and 34% (32%–37%, n = 8) of length (tables 3, 10); length of movable finger 37% (25%–45%, n = 8) greater than length of manus. Chela with three or four carinae evident (fig. 43); dorsomedian carina reduced to vestigial granules proximally or absent; digital carina weakly developed, granular; secondary accessory and retroventral carinae incompletely fused, slight disjunction evident in proximal third; retroventral carina weakly developed, granular, aligned parallel to longitudinal axis of chela, with distal margin connected to retrolateral movable finger condyle; ventromedian carina reduced to vestigial granules proximally; other carinae absent; intercarinal surfaces smooth. Fixed and movable fingers, dentate margins sublinear, no proximal “gap” evident when closed; median denticle rows comprising eight (7 or 8, n = 68) oblique and slightly imbricated subrows (tables 3, 4, 10), decreasing in length distally; each subrow comprising large retrolateral denticle proximally (absent from proximal subrow, for total of six or seven retrolateral denticles on fixed and movable fingers), several small median denticles, and large prolateral denticle distally, slightly offset (total of seven or eight prolateral denticles on fixed and movable fingers); terminal (prolateral) denticle of first subrow enlarged; accessory denticles absent.

Trichobothria: Orthobothriotaxic, Type D, β configuration, trichobothrium d 2 situated on femur dorsal surface, d 3 and d 4 in same axis, parallel and closer to retrodorsal carina than d 1, angle formed by d 1, d 3 and d 4 opening toward prolateral surface, with the following segment totals (figs. 42, 43): femur, 12 (6 dorsal, 3 prolateral, 3 retrolateral); patella, 10 (3 dorsal, 1 prolateral, 6 retrolateral); chela, 13 (5 manus, 8 fixed finger). Total number of trichobothria per pedipalp, 35. Five trichobothria on femur, i 4, d 1, d 2, d 4, and d 6, one on patella, est 1, and one on chela fixed finger, ib 2, noticeably smaller than others (“petite”). Trichobothrium Et 1 situated distally on manus, aligned with or proximal to movable finger condyle; eb situated on fixed finger, slightly distal to movable finger condyle; esb 2 situated in proximal third of fixed finger, between first and second most proximal retrolateral denticles of median denticle row.

Legs: Leg I maxillary lobes (coxapophyses), distal margins rounded, unmodified (not spatulate or dilate) anteriorly, terminating flush with lobes of leg II (figs. 40B, 41B). Legs I and II tibiae, retrolateral margins each with scattered macrosetae, without spurs (fig. 15D); III and IV without spurs. Basitarsi with few scattered macrosetae, pro- and retrolateral rows of long spinules, and pair of pro- and retrolateral pedal spurs. Telotarsi with pair of slightly irregular ventrosubmedian rows of long spinules; proventral and retroventral rows of macrosetae absent, only few scattered macrosetae laterally; laterodistal lobes reduced and truncated; median dorsal lobe very short; ungues short, distinctly curved, equal in length; unguicular spur (dactyl) pronounced, pointed.

Sternum: Sternum, Type 1, pentagonal, length 15% (7%–21%, n = 9) greater than posterior width (tables 3, 10), lateral margins sublinear, ventral surface shallowly concave, posteromedian depression round (fig. 14B, D, F).

Pectines: Three marginal (anterior) lamellae, proximal sclerite considerably longer, distal sclerite short (fig. 14B, D, F); 8/8 (7 or 8, n = 15) (♂) or 7/7 (5–7/5–8, n = 34) (♀) median lamellae (tables 3, 10); fulcra present, very small. Proximal median lamella and basal pectinal tooth unmodified. Pectinal teeth present along entire posterior margin of each pecten; 9/9 (8–10/8 or 9, n = 18) (♂) or 7/8 (6–8/6–9, n = 46) (♀) teeth. Pectinal peg sensillae long, cylindrical, tubular, or bottle shaped, and rounded distally, without pair of laterodistal processes; sensillar sockets smooth.

Genital operculum: Opercular sclerites completely separated, prominent genital papillae visible along entire length (♂) or absent (♀) (fig. 14B, D, F). Genital plugs observed in some females.

Male reproductive organs: Unknown.

Female reproductive organs: Ovariuterus comprising reticulate mesh of six cells. Oocytes contained in sessile follicles directly contacting ovaruterine tubes.

Mesosoma: Pretergites surfaces smooth and shiny. Posttergites I–VI surfaces smooth or nearly so, acarinate, each with pair of shallow submedian depressions (figs. 40A, 41A); VII surface sparsely granular, with pair of granular dorsosubmedian and dorsolateral carinae reaching posterior margin of segment. Sternites III–VII surfaces entirely smooth, acarinate (figs. 40B, 41B), with scattered macrosetae, posterior margins with sparse row of macrosetae; III–VI, respiratory spiracles (stigmata) small, oval (fig. 14B, D, F); V posteroventral margin with pale, raised, triangular surface; VII width 34% (25%– 45%, n = 8) greater than length (table 10).

Metasoma: Metasoma relatively short, total length 24% (18%–44%, n = 9) greater than combined length of prosoma and mesosoma (tables 3, 10); segments I–V progressively increasing in length, I wider than long, width of length for segment I, 101% (95%–116%, n = 9); II, 76% (68%–86%); III, 65% (59%–72%); IV, 48% (44%– 53%); and V, 23% (20%–25%). Metasoma with few short macrosetae. Ten carinae on segments I–III, eight on IV, and four on V (figs. 17D, E, 19D, E, 21D, E). Dorsosubmedian carinae moderately developed, granular throughout length of segments I–IV, absent on V; converging posteriorly. Dorsolateral carinae moderately developed, granular throughout length of segments I–IV, obsolete on V; converging posteriorly on I and V, subparallel on II–IV. Dorsosubmedian and dorsolateral carinae of segments I–IV not terminating posteriorly with enlarged, spiniform granules, granules similar to preceding granules. Median lateral carinae complete, granular throughout length of segment I, partial, becoming obsolete anteriorly on II and III, absent on IV and V. Ventrolateral carinae moderately developed, granular, becoming obsolete anteriorly on segments I and II, continuous throughout length of III–V; converging posteriorly on I and V, subparallel on II–IV. Ventrosubmedian carinae absent on segment I, obsolete, costate on II, moderately developed, granular throughout length of III–V; subparallel on II and III, converging posteriorly on IV and V. Ventromedian carina absent on segment V. Intercarinal surfaces smooth.

Telson: Telson large, suboval (figs. 17D, E, 19D, E, 21D, E). Vesicle elongate, 32% (20%– 45%, n = 9) wider than metasomal segment V (tables 3, 10), with flattened dorsal surface and rounded ventral surface, height 37% (35%–39%, n = 8) of length; dorsal, lateral, and ventral surfaces smooth or nearly so (♀); anterodorsal lateral lobes (“vesicular tabs”) obsolete; subaculear tubercle absent. Aculeus short, shallowly curved, 31% (29%–33%, n = 8) of telson length. Venom glands thin walled, simple, and unfolded.

Intraspecific variation: The only morphological difference between the material from the two caves, which does not constitute ontogenetic variation or sexual dimorphism, concerns the median denticle rows on the fixed and movable fingers of the pedipalp chela, which comprise eight subrows in material from Tiên SƠn, the type locality of V. canhi , and seven subrows in material from Động Thiên ĐƯờng (Paradise Cave), the type locality of V. aurantiacus , V. quinquemilia , and V. thienduongensis (tables 3, 4, 10). This single difference is not considered sufficient to merit recognition at the species level, in the face of morphological similarity (fig. 8) and low genetic divergence (fig. 9; table 12).

Ontogenetic variation: Immature stages, including the types of V. canhi , V. quinquemilia , and V. thienduongensis , are paler in color and less sclerotized, and the posteroventral margin of mesosomal sternite V does not exhibit a pale, raised, triangular surface as in the adult stage. However, immature stages are easily sexed by examination of the genital aperture.

Sexual dimorphism: The genital papillae, visible the entire length and thus completely separating the two sclerites of the genital operculum (fig. 14B), are the characters of primary external sexual dimorphism in the male. The opercular sclerites are also completely separated in the female, although genital papillae are absent (fig. 14D, F). The only apparent secondary sexual characters observed in the male are the slightly better developed pectines, the median lamellae of which are more usually numerous and the teeth somewhat larger, and usually more numerous (fig. 14B, D, F; tables 3, 5, 10).

DISTRIBUTION: Endemic to the Bố Trạch District of Quảng Bình Province, Vietnam, where it has been recorded from two caves, Tiên SƠn and Động Thiên ĐƯờng (Paradise Cave), near SƠn Trạch , in the Phong Nha-Kẻ Bàng National Park (fig. 7). The caves are situated in a karstic landscape, in tropical forest at an elevation of 200– 250 m (fig. 4A).

ECOLOGY: Specimens from Tiên SƠn were collected with UV detection in the dark zone of the cave, ca. 200–500 m from the entrance, sitting in rock crevices or under small stones, in a moist area with abundant speleothems, including dripstone and flowstone formations, stalactites, and stalagmites (fig. 4E). None were found in dry areas of cave. Specimens from Động Thiên ĐƯờng were also collected with UV detection in the dark zone, but much deeper, at sites between 1–5 km from the cave entrance, under rocks, in limestone cracks, or walking on the surface. Động Thiên ĐƯờng is approximately 31 km in length.

Vietbocap canhi is an obligate troglobite, characterized by the absence of ocelli and pigmentation, attenuation of the pedipalps and legs, and slight enlargement of the telson ( Prendini, 2001b; Volschenk and Prendini, 2008). It appears to be the most cave-adapted member of the family, displaying the most elongated pedipalp chela and distinct dorsoventral compression of the carapace.

CONSERVATION STATUS: Vietbocap canhi is presently known from two caves, ca. 2.5 km apart, in the Phong Nha-Kẻ Bàng National Park. Whereas Tiên SƠn is a relatively small cave, Động Thiên ĐƯờng is very deep (ca. 31 km long), and V. canhi has been collected up to 5 km from the entrance of the latter. The anterior section of both caves is heavily disturbed: a concrete walkway and metal railings have been installed, and the cave brightly illuminated to display the speleothems. Few scorpions were observed in the illuminated parts of either cave. Access is restricted beyond the illuminated sections of both caves, however, where the habitat remains largely undisturbed. Despite the high level of protection afforded to its habitat, this highly stenotopic species is characterized by an acute restriction in both its area of occupancy and number of known localities: it is known to exist at only two locations, the extent of occurrence is less than 5000 km 2, and the area of occupancy less than 500 km 2. Therefore, it remains prone to the effects of human activities (or stochastic events, the impact of which may be increased by human activities, e.g., climate change) within a very short period of time in an unforeseeable future, and potentially faces a high risk of extinction in the wild, warranting its assignment to the Endangered category of the IUCN Red List.

REMARKS: Lourenço and Pham (2012) described V. thienduongensis from Động Thiên ĐƯờng, a cave ca. 2.5 km from Tiên SƠn, the type locality of V. canhi . Lourenço and Pham (2012: 84) separated V. thienduongensis from V. canhi as follows:

(i) bigger size and distinct morphometric values; (ii) complete and more strongly marked circumocular sutures; (iii) chela fingers proportionally shorter (ratios of chela length/ movable finger length 7.1/4.2 = 1.69 for V. canhi and 8.3/4.6 = 1.80 for V. thienduongensis sp. n. and with 8 subrows of granules vs. 7 sub-rows); (iv) sternum only slightly longer than wide (ratio 1.15 for V.canhi and 1.30 for V. thienduongensis sp. n.); (v) metasomal segments less carinated and granulated and with a weaker chaetotaxy; (vi) pedipalp carinae better marked; (vii) pectines shorter and more bulkier with 8 teeth. Moreover, the caves where the species have been found are totally isolated from one other and belong to distinct cave systems. Given that the two caves are only a few kilometres apart, it can be suggested that both Vietbocap species may have a common epigean ancestor that colonized the caves independently.

Lourenço et al. (2018) subsequently described the female of V. thienduongensis , and two new species from deeper in the same cave. Whereas the specimens of V. thienduongensis were collected 750–1800 m from the cave entrance, the holotype of V. aurantiacus was collected 3000 m from the entrance, and the types of V. quinquemilia , 5000 m from the entrance. According to Lourenço et al. (2018: 269, 271, 272):

Vietbocap thienduongensi s and Vietbocap aurantiacu s sp. n. are the two most geographically close species found in the cave, distant of 1.0 to 1.5 km. V. aurantiacus sp. n. can, however, be distinguished by a number of features: bigger size (35.8 vs 23.9 mm) and distinct morphometric values …; darker coloration, more to orange-yellow; anterior mar- gin of carapace not depressed; sternum longer than wide …; metasomal segments and pedipalps better carinated and granulated; sternite V with a conspicuous white posterior inflated triangular zone; moderate serrula on chelicera movable finger.…

Vietbocap quinquemilia sp. n. is geographically separated of Vietbocap aurantiacus sp. n. by 2 km. Their general morphology although similar presents a number of differences and in fact V. quinquemilia seems more closely related to V. thienduongensis . This new species can however be characterized by a number of particular features: small size (only 20.2 mm for female) and distinct morphometric values (see measurements and ratios following the description); a very pale coloration almost whitish; this is the paler species known for the genus; median ocular tubercle on carapace only slightly depressed; cheliceral serrula moderately marked; tergites globally smooth; pedipalp carinae very weakly marked.…

It is difficult to estimate from the sole morphological study of these “populations” of Vietbocap living in the Thien Duong cave what is their precise degree of differentiation … Consequently, the question to be addressed is: are we faced with species, subspecies or only morphs of a large polymorphic species? For three of these populations, a specific status is here suggested in association with their possible allopatric distribution, though the number of available specimens is small to evaluate the robustness of the observed differences.… The presence of syntopic and closely related troglobitic species of a same genus in a same cave [sic] is quite exceptional. Molecular approaches will be necessary to evaluate the robustness of the observed differences between the species which have been recognized.

The hypothesis that three allopatric populations or species of Vietbocap inhabit Động Thiên ĐƯờng was tested and falsified in the present study by comparing DNA sequences of two nuclear (18S-ITS and 28S) and three mitochondrial (12S, 16S, and COI) gene loci from five samples collected at several sites along a transect 1–5 km from the entrance. The extremely low genetic divergence among the samples along this transect (fig. 9; table 12) are consistent with panmixis. In addition, the same loci were sequenced from three samples collected in Tiên SƠn, the type locality of V. canhi , only 2.5 km away. Similar levels of divergence among the samples from Tiên SƠn, and between those samples and the samples from Động Thiên ĐƯờng, falsified the hypothesis that the two caves harbor different species, refuting the unsubstantiated statement that the caves “are totally isolated from one other and belong to distinct cave systems.” The assumption that species occurring in different caves must be heterospecific, also known as the “caves as islands” paradigm ( Mammola, 2019) suggested earlier by others (e.g., Francke, 2009a), is problematic for two reasons, noted earlier. Firstly, geography is not heritable and cannot comprise part of a taxon diagnosis, regardless of the presence or absence of morphological (or genomic) differences. Secondly, no conclusive evidence has been presented that the caves are disconnected or that these scorpions might not occur in other caves or passages in the 2.5 km between them. Several caves and cave networks in Southeast Asia are far longer than the distance between Tiên SƠn and Động Thiên ĐƯờng, e.g., Hang SƠn Đoòng (over 9 km long), Tham Xe Bang Fai (11 km long), and Phong Nha Cave (over 44 km long). Even Thiên ĐƯờng is more than 20 km long. As noted earlier, in attributing islandlike properties to caves, researchers should consider the presence of subterranean connections, as well as the vagility of the species of interest ( Mammola, 2019). A network of fissures connecting two caves would make it difficult to consider the scorpion populations inhabiting them, to be isolated from one another.

Multivariate statistical analysis of the morphometric data presented by Lourenço and Pham (2010, 2012) and Lourenço et al. (2018), together with new data (tables 3–5, 10; appendices 4, 6, 7), was similarly unable to discriminate among the individuals from the two caves, which clustered together across a morphospace comparable to that of other pseudochactid spe- cies (fig. 8). It is apparent that ontogenetic differences were mistaken as diagnostic by Lourenço and Pham (2010, 2012) and Lourenço et al. (2018). Putatively diagnostic differences concerning size and morphometrics (table 3), coloration, granulation and/or carination, and the relative development of the circumocular sutures (affected by the sclerotization of the carapace tegument) reflect different stages of sexual maturity. Smaller size (and associated morphometric differences; tables 3, 10; appendices 4, 6, 7), paler coloration, weaker granulation and/or carination, and weakly developed circumocular sutures, as exemplified by the types of V. canhi and V. quinquemilia , are consistent with the immature stages, whereas larger size (and associated morphometric differences; tables 3, 10; appendices 4, 6, 7), darker coloration, stronger granulation and/or carination, and well developed sutures, as well as the presence of a pale, raised, triangular surface on the posteroventral margin of sternite V, exemplified by the holotype of V. aurantiacus , are consistent with the adult stage. The only characters that are ontogenetically invariant and offer any potential for species diagnosis are the counts of median denticle subrows on the fixed and movable fingers of the pedipalp chela, and the counts of pectinal teeth and lamellae. However, setting aside the absence of a statistical sample, the variation in these counts (e.g., a difference of one denticle subrow between individuals from the two caves, or of one pectinal lamella or tooth between individuals of the same sex in the same or different caves; tables 3–5) spans the normal levels of variation observed in other scorpion taxa, including pseudochactids.

In view of the overwhelming molecular and morphological evidence that the scorpions inhabiting both caves are conspecific, the following new synonyms are proposed: Vietbocap thienduongensis Lourenço and Pham, 2012 = Vietbocap canhi Lourenço and Pham, 2010 , syn. nov.; Vietbocap aurantiacus Lourenço et al., 2018 = V. canhi , syn. nov.; Vietbocap quinquemilia Lourenço et al., 2018 = V. canhi , syn. nov.

MATERIAL EXAMINED: VIETNAM: Qu ảng Bình Prov. : Bố Trạch Distr. : Phong Nha-Kẻ Bàng National Park : Tiên SƠn (Cave), 17°31′58.8″N 106°16′01.2″E, 200 m, 23.ii.2012, L. Prendini and V. A. Dang, dark zone of cave, ca. 200–500 m from entrance, UV detection in moist cave environment with abundant dripstone and flowstone formations, stalactites and stalagmites, specimens usually sitting in rock crevices or under small stones, mostly in moist situations (near areas where water collects from dripstone formations), none found in dry areas of cave, 7 ♀, 2 subad. ♂, 1 subad. ♀, 4 juv. ♂, 4 juv. ♀, pedipalp fragments ( AMNH), 3 juv. ♀ ( AMCC [ LP 11270 , 16750 , 16751 ]) ; Thiên ĐƯ ờng ( Cave ), 200 m, 12.xi.2011, ex D.-S. Pham, cave, No. 1279, 1 juv. ♀ ( AMCC [ LP 11348 ]), Động Thiên ĐƯ ờng (Paradise Cave), 17°31′11.1″N 106°13′23″E, 248 m, 12–13.xi.2018, S.F. Loria, V. L. Ehrenthal, B.Đ. Tr ần, and H. V. DƯƠng, blacklight in cave, specimens collected between 1 km and 5 km deep in cave, walking on ground, under rocks or in limestone cracks, ca. 1 km from cave entrance, 1 ♀ ( AMNH), 1 subad. ♀ ( IEBR), [leg] ( AMCC [ LP 16533 ]), between 1 km and 5 km from cave entrance, 1 subad. ♂ ( IEBR), [leg] ( AMCC [ LP 16535 ]), 1 subad. ♀ ( AMCC [ LP 16536 ]), ca. 5 km from cave entrance, 1 juv. ♂ ( PNKB), [leg] ( AMCC [ LP 16534 ]), 1 juv. ♀ ( PNKB), [leg] ( AMCC [ LP 16537 ]) .