Chaerilus mainlingensis Di & Zhu, 2009

Tang, Victoria, 2025, Current challenges and preliminary morphological reassessment of the genus Chaerilus Simon, 1877 in China (Scorpiones: Chaerilidae), Euscorpius 406, pp. 1-89 : 15-16

Chaerilus mainlingensis Di & Zhu, 2009

( Tables 1–2) http://zoobank.org/lsid:zoobank.org:act:E41C0B04-

03B5-4D11-9167-88BD35CE1BA3

Chaerilus mainling *: Di, 2009: 98, 102–103; Sun, 2010: 101.

Chaerilus mainlingensis : Di, 2009: 131–133; Di & Zhu, 2009: 97–101; Sun, 2010: 104–105; Kovařík, 2012: 2, 13; Kovařík & Ojanguren-Affilastro, 2013: 131–132, 138; Di et al., 2013: 52 , 55, 57, 88; Di et al., 2014: 5, 9, 14; Yin et al., 2015: 42, 48, 49; Di et al., 2015: 111; Tang, 2022a: 55; Tang, 2022b: 3, 14; Tang, 2025: 16 .

*Di’s dissertation (2009) was submitted on 24 th May while

Di & Zhu (2009) was published on 13 th December, so “ C.

mainling ” is not an ISS.

TYPE MATERIAL (Di & Zhu, 2009: 97) [lost]. China, Tibet Autonomous Region, Nyingchi City, Mainling City, Milin Town , Gongbuwang Manor, 29°15'30.0''N 94°17'54.3''E (approximated), 2♀ , MHBU.

MATERIAL EXAMINED. None.

DIAGNOSIS. TL ca. 40.36–40.72 mm for ♀; ♂ unknown. General color reddish brown to blackish brown. Two pairs of lateral ocelli and one pair of median ocelli. Carapace and tergites granular; CAM weakly concave; sternite III – VI smooth, VII subgranular and tetracarinate. Metasoma I– V with carinae 10-8-8-8-7. PTC 3–4 in ♀. VADC of cheliceral movable/ fixed fingers 7–8/6. Pedipalp chela ChL/W ca. 2.4–2.75 in ♀; manus with D 1, D 4 – 5, and V 1 , 3 present and granular, E and I obsolete; D 3 highly obsolete as an unridged dark stripe; DSC of movable finger 7, dorsal edge of movable finger straight .

CURRENT ASSESSMENT OF TAXONOMIC VALIDITY. Valid, but pending the designation of a neotype.

REMARKS. The description of this species was based on only two adult females, which remain the sole specimens known to date. Consequently, the available information is largely confined to the original description, and subsequent publications have been predominantly misleading. However, confusions nonetheless present in the original paper itself. Di & Zhu (2009: 98) described the chela of C. mainlingensis as “… dorsal internal [= D 5], digital [= D 1], dorsal external, ventral internal [= V 3], ventral external [= V 1] carinae with smooth granular, external secondary [= E], external and interomedian [= I] carinae obsolete or vestigial …”. In a different section on the same page, the authors stated that “… dorsal secondary carinae [= D 3] of the chela obsolete as a black stripes without ridges …”, suggesting that the correct description should likely read: “ dorsal secondary [= D 3], external secondary [= E] and interomedian [= I] carinae obsolete or vestigial ”. This leaves their “dorsal external” carina as “dorsal marginal” carina (= D 4). In contrast, Kovařík & Ojanguren-Affilastro (2013: 138) diagnosed this species with “8 granulated carinae”, and reduced its PTC to 3 (3–4 in Di & Zhu (2009: 98)).

In their dichotomous keys, Di et al. (2013: 88) differentiated this species from C. dibangvalleycus by one of the two characters (the other being pedipalp femur longer than carapace in C. mainlingensis , and the opposite in C. dibangvalleycus ) as follows (recycled by Di et al. (2014: 14) and Yin et al. (2015: 49)):

“… 8–9 minute teeth on inner ventral margins of movable and immovable fingers respectively … C.

dibangvalleycus”

“… 7–8 minute teeth on inner ventral margins of movable and immovable fingers respectively … C. mainlingensis ”

They used “respectively” to refer to the movable and fixed fingers while providing only one range for both, which is puzzling. At first glance, this description seems to pertain to the chelicerae, as the terms “minute teeth” and “inner ventral margins” are typically used to describe cheliceral dentition (VAD; pedipalp movable fingers do not have dentate inner ventral margins). However, they cited Bastawade (2006: fig. 5) and Di & Zhu (2009: fig. 11), both depicting the movable finger of pedipalp chela. This is rather baffling as Bastawade did not provide the DSC of fixed pedipalp finger. In Bastawade (2006: 451, right column), the author merely mentioned that “…Pedipalp… immovable finger … provided bellow [below] with double row of minute dentition; movable finger … provided with double row of minute dentition …”. On page 454 (op. cit., left column), the author provided a DSC of 7–8 for the pedipalp movable finger of C. dibangvalleycus . In Di & Zhu (2009: 98, left column), the authors stated “… dentate margins of fixed and movable fingers of pedipalp chela with seven rows of granules …” for C. mainlingensis . Neither datum accords with the keys originally provided by Di et al. (2013). However, if one attempts to locate those values in the respective papers, it can be found that in Bastawade (2006: 451, left column), the author stated “… Chelicera … four and eigth [eight] to nine minute teeth on inner ventral margins of movable and immovable finger s respectively …” (though he later shifted these counts to 5 and 10 in his interspecific comparison; op. cit.: 454), and in Di & Zhu (2009: 98), the authors stated “… Chelicerae … ventral inner edges of movable finger with six medium-size teeth and one or two obsolete small teeth …” (i.e., 7–8 VAD for cheliceral movable finger). Additionally, their figure 4 showed six VAD for the fixed cheliceral finger of C. mainlingensis . If Di et al. (2013) in fact referred to those values, they would essentially be comparing the VADC of fixed cheliceral finger of C. dibangvalleycus against that of the movable cheliceral finger of C. mainlingensis , which is inscrutable, as the senior author of that paper was the same author described C. mainlingensis . To clarify, the correct meristics for the two species are as follows (movable/fixed): (1) C. dibangvalleycus : cheliceral finger, 4–5/8–10, pedipalp chelal finger, 7–8/?; (2) C. mainlingensis : cheliceral finger, 7–8/6, pedipalp chelal finger, 7/7.

Despite this, C. mainlingensis itself is well distinguished according to the original data alone. The original authors compared it with C. insignis , C. pictus , C. truncatus , and C. tryznai based on mostly valid characters, particularly the DSC, which effectively differs it from C. insignis , C. pictus , and C. truncatus . Both C. insignis and C. truncatus are also geographically distant from the Tibetan region where C. mainlingensis occurs. The absence of D 3 and carinate sternite VII corroborates its distinctions from the geographically closest C. tryznai within this set of congeners. The diagnostic table summarized herein highlights these two characters as key differentiators between the two species. Within Tibetan Chaerilus , absence of D 3 is so far observed in C. dibangvalleycus , C. mainlingensis , and C. tricostatus . Based on the original data, C. tricostatus can be easily separated from C. mainlingensis by a higher DSC alone, while C. dibangvalleycus is supposedly distinguished by its higher VADC on both cheliceral fingers and slightly higher female PTC. However, it is also worth mentioning that the denticle subrows of movable finger illustrated for C. mainlingensis might be either abnormal (cf. Figs. 128–129 ) or inaccurate, as no clear imbrication could be discerned between most adjacent subrows, and several subrows appeared atypically elongated. If DSC turns out to be an erroneous diagnostic, the validity of C. mainlingensis might still be defended by its slightly lower female PTC (no pectinal anomaly was observed in the original illustration). Although the current investigation revealed that C. conchiformus is the geographically closest species ( Fig. 1 ), the two species can be readily differed by the pedipalp chela alone. Nevertheless, since no photograph was provided for this species, further investigations are warranted to definitively confirm its validity, particularly against C. dibangvalleycus .

DISTRIBUTION. Known only from the type locality; Gongbuwang Manor of Milin Town, Mainling City, in Nyingchi City.

Figures

Figure 1. Map showing the known distribution of Chinese Chaerilus species. Black lines represent China national border, downloaded from GitCode. Yellow lines represent county-level division in Nyingchi and Shannan cities, downloaded from Tianditu. Red dash lines represent disputed area (Arunachal Pradesh), downloaded from Natural Earth. The locality of C. pseudoconchiformus is represented by the examined adult pair. Localities of C. conchiformus include those of an examined specimen, iNaturalist observations, and published records (see text). Localities of other species include those of iNaturalist observations and published records only (see text). Insets: left above corner, closeup of type locality of C. herta sp. n.; right bottom corner, localities of the studied C. cf. tryznai (white cross) and C. cf. wrzecionkoi (white triangle).

Figures 120–129. Representative pectines (under white light) and pedipalp movable fingers (under UV light against black cloth; red number, complex subrow; green number, simple subrow) of examined males of Chaerilus herta sp. n. Figures 120–123. Pectines of males showing 5/5 (120), 6/6 (121), 5/6 (122), and 6/5 (123) teeth (note that the left/right PTC in the figures should be switched as such because the specimens are viewed in the current orientation). Figures 124–125. Movable fingers showing a loss of an EPD (red circles). Figure 126. Movable finger showing an EPD positioned externally to the connected 9th and 10th subrows. Figure 127. Movable finger showing an EPD integrated into the 8th and 9th subrows. Figure 128. Movable finger showing abnormally elongated 1st and 2nd subrows. Figure 129. Movable finger showing at least the loss of at least one EPD along the current 2nd subrow.