Globochthonius Beier 1931
Creators: name: Zaragoza, Juan A.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Pseudoscorpiones
Chthoniidae
Globochthonius

description: Genus Globochthonius Beier, 1931 n. stat.
Diagnosis. Genus of the tribe Chthoniini with lagyniform chela (sensu Judson 2007), chelal hand with continuous dorsal constriction from trichobothria ib / isb towards the base of fixed finger; base of chelal hand often with a pronounced hump dorso-paraxially (Fig. 18); without a ventral hollow before base of movable finger; base of chelal hand abruptly constricted paraxially; without a medial protuberance (ip) between chelal condyles; proximal portion of chelal hand with 4 setae in adults, seta ph3 present, chaetotaxy 4:5:4 (Figs 17‒18). Pedipalpal fingers of about the same length, the movable slightly shorter than the fixed, fixed finger usually forming an obtuse angle apically, almost straight, respect to finger axis; dental rows homodentate, bearing spaced and slightly or distinctly reclined teeth, subdistal tooth (mt) of fixed finger not modified; tip of fixed finger with an accessory tooth (td) on antiaxial face; tip of fixed chelal finger of both sexes and, at least, tritonymphs with a weak hollow on paraxial face, in both sexes and at least in tritonymphs without subdistal protuberance (sp) (except in a single known population); antiaxial sensory setae (as) usually very short and close together in epigean species; coupled sensilla pc between trichobothria sb and b, or level with or slightly distad of sb; base of movable chelal finger without an enlarged condyle, proximally with more or less strongly sclerotized apodeme. Lyrifissure ma1 always present, ma2 and hp usually present. Anterior margin of carapace more strongly dentate between median macrosetae, weakly prominent, without epistome. Coxae II and III with coxal spines; bisetose intercoxal tubercle present between coxae III and IV; distal marginal seta of pedipalpal coxa disk distinctly longer than the distal marginal seta of coxa I; sternite III of males and females usually with 8 marginal macrosetae, and a smaller seta (microsetal in size) on each side. No median hiatus in each row of internal genital guard-setae. Comparison with Chthonius -related genera as in the key and Table 1.
Type species. Chthonius globifer Simon, 1879.
Distribution. Southern and South-eastern Europe: Bosnia-Herzegovina, Croatia, France, Italy, Macedonia, Romania, Serbia, Slovenia, Switzerland.
Remarks. Globochthonius was originally created as a subgenus by Beier (1931). It differs from the other Chthonius- related genera by the following combination of characteristics: base of chelal hand usually with a pronounced hump dorso-paraxial; chelal teeth usually spaced and upright in both fingers; movable chelal finger with apodeme; lyrifissures ma1 and ma2 present (exceptionally ma2 absent); 4 setae in the proximal portion. These characteristics apply in part to both Chthonius s. st. and Ephippiochthonius, but Globochthonius differs from both of them by the chelal hand shape, which is unique within the Chthonius -related group of genera. Moreover, it differs from Chthonius by the presence of upright separated teeth on both chelal fingers and a more strongly developed apodeme, and from Ephippiochthonius by the combination of 4 setae in the proximal portion of the chelal hand and the absence of a medial protuberance (ip) between the chelal condyles.
Globochthonius species often display high variability in important characteristics. Ćurčić (1973, 1974) pointed out the existence of two species-groups within Globochthonius, one with close-set teeth, distinctly reclined backwards and another with separated upright teeth. He considered the former to be the primitive state, from which the latter evolved. The movable chelal finger apodeme, although always present, can exhibit great interspecific differences in its length. Muchmore (1965, 1974, 1976) studied different populations of the genus Kleptochthonius and distinguished three groups of species, differentiating between them by a short, large or large and bifurcated apodeme, leading him to conclude (Muchmore 2000) that a restudy of some characters in Kleptochthonius, including the shape of the apodeme, “will provide evidence of separate evolutionary lines within the genus”. During this study, a small collection of specimens from Italy and Switzerland previously assigned to the species Globochthonius globifer (Gardini 2010) has been examined, amongst which a few samples from Italy (Piedmont, Biella province, Santuario di Oropa) containing males that exhibit a weak hollow on the paraxial face of the fingertip with a subdistal protuberance (sp) (Fig. 20) (the same occurs in males from Simplon, Switzerland), as opposed to its absence in males from other Italy localities (Piedmont, Cuneo province, Crissolo) (Fig. 19). The absence of this characteristic was considered by Gardini (2013) as an additional distinction between Globochthonius and Ephippiochthonius. Unfortunately the two syntype males of G. globifer in MNHN were mounted on slides by B.P.M. Ćurčić and are no longer in a suitable state to allow this character to be checked (M. Judson, in litt.). In addition, the specimens from Santuario di Oropa lack lyrifissure ma2. These variations within the genus Globochthonius, together with dental development differences found by Ćurčić (1974), deserves more detailed study.
The transfer of Chthonius (Ephippiochthonius) poeninus Mahnert, 1979 to the genus Globochthonius (Gardini 2013) is herein confirmed by the presence of 4 setae in the proximal row of the chelal hand.
description: Published as part of Zaragoza, Juan A., 2017, Revision of the Ephippiochthonius complex in the Iberian Peninsula, Balearic Islands and Macaronesia, with proposed changes to the status of the Chthonius subgenera (Pseudoscorpiones, Chthoniidae), pp. 1-221 in Zootaxa 4246 (1) on pages 21-22, DOI: 10.5281/zenodo.437611