Chaerilobuthus knodelorum Lourenco 2018
Creators: name: Xuan, Qiang
name: Prendini, Lorenzo
name: Engel, Michael S.
name: Cai, Chenyang
name: Huang, Diying
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Scorpiones
Chaerilobuthidae
Chaerilobuthus
Chaerilobuthus knodelorum

description: Chaerilobuthus knodelorum Lourenço, 2018
(Figs 27–31, 39)
Chaerilobuthus knodelorum Lourenço, 2018: 2, 3, figs 1–12.
Type material: Holotype: one juv. (sex unknown) (personal collection of KlausPeter Brucksch, Kuranda, Australia), Cretaceous (Cenomanian) burmite: MYANMAR: Kachin State (precise locality unknown).
Diagnosis: The following combination of characters is diagnostic for C. knodelorum: carapace anterior margin sublinear (Figs 28A, 29A); lateral ocelli not protruding, macular (Fig. 29A); cheliceral finger ventral surface with serrula extending almost entire length (Fig. 29B); pedipalp chela relatively wide, ratio of chela length: width less than 4 (Figs 28C, F, 29E); leg telotarsi ventrosubmedian rows with very long spinules (Fig. 29G, H, J); pectinal lamellae relatively wide, pectines each with five, relatively large teeth (Fig. 29C); mesosoma long, ratio of mesosoma: carapace length greater than 2.5.
Description: Based on the material examined (NIGP 200657).
Carapace: Anterior margin with few, short microsetae; anteromedian depression narrow, shallow; anterosubmedial depressions absent (Fig. 28A); lateral ocular carinae absent; posteromedian and posteromarginal sulci distinct (Fig. 30A); posterior margin slightly recurved medially (Figs 28A, 29A); surfaces almost smooth to sparsely and finely granular (Figs. 28A). Median ocular tubercle situated anteromedially; median ocelli absent; one pair of large posterolateral major lateral ocelli present.
Coxosternal region: Surface smooth, sparsely covered in macrosetae (Fig. 28B). Leg I maxillary lobes (coxapophyses) distal margins slightly curved and dilate anteriorly, adorned with serrula (Fig. 39E). Sternum pentagonal; lateral margins sublinear, parallel; posterior margin slightly recurved; ventral surface flat, without distinct concave region or median sulcus; posteromedian depression relatively wide, shallow (Fig. 30B).
Chelicerae: Cheliceral dentition partly visible; moveable finger with long dorsal distal (dd) denticle, small dorsal subdistal denticle, stout dorsal median denticle and long ventral distal (vd) denticle; fixed finger with long distal denticle and small subdistal denticle (Fig. 28A). Moveable finger with prominent serrula, comprising moderately long spinules and extending almost entire length of ventral surface (Fig. 29B).
Pedipalps: Segments gracile; surfaces finely granular (Fig. 27). Femur with three carinae evident; prodorsal carina distinct, markedly serrate; retrodorsal carina distinct, slightly serrate; proventral carina smooth, costate (Figs 28F, 31). Patella with six carinae evident; prolateral surface, dorsoventral ‘vaulted’ projection (‘anterior process’) distinct with obsolete pair of apophyses or tubercles (‘patellar spurs’), each possessing one macroseta; retrodorsal, retromedian, and retroventral carinae distinct, smooth and costate; prodorsal carina obsolete (Figs 29D, 31). Chela relatively robust (CL/ CW = 3.75, Appendix2); manus globose; chela with five carinae evident; digital carina incomplete, distinct on fixed finger, obsolete on manus; prodorsal carina distinct, markedly serrate; promedian carina distinct, comprising several prominent spiniform granules distally; retroventral carina obsolete, smooth and costate (Figs 28C, F, 29E, 31); dorsomedian, dorsal secondary, subdigital, proventral, retromedian and ventromedian carinae absent or obsolete. Fixed and moveable fingers median denticle rows visible distally, each comprising oblique, slightly imbricate subrows of c. 13 small denticles, separated by large serrate prolateral and retrolateral denticles (Fig. 29F). Trichobothrial pattern Type D, β configuration (Fig. 31). Pedipalp femur with four trichobothria visible, two d and two e trichobothria. Patella with nine trichobothria visible, including two d, one i, and six e trichobothria; trichobothrium i 1 situated distal to trichobothrium d 3. Chela with 11 trichobothria visible; fixed finger with one d, two e, and three i trichobothria; manus with four E and one V trichobothria; trichobothrium Et 1 situated distally on manus, almost aligned with or proximal to moveable finger condyle; trichobothrium eb situated on fixed finger, slightly distal to moveable finger condyle; trichobothrium esb situated submedially to slightly distally on fixed finger; trichobothrium V 2 situated distally on manus and near retroventral carina.
Legs: Tibia lateral and ventral surfaces each with scattered macrosetae (Fig. 29H–J). Basitarsi each with prominent pedal spurs (Fig. 29G–J) and pair of spinule rows, each comprising c. 10 relatively long spinules, distally (Fig. 29G–J). Ungues moderately long, distinctly curved; dactyl pronounced, pointed (Fig. 29H–J).
Pectines: Pectines very short, not extending beyond coxa of leg IV (Fig. 29C, 30B). Three marginal lamellae and four median lamellae; surface sparsely covered in macrosetae; longitudinal suture between marginal and median lamellae distinct. Fulcra absent or obsolete. Teeth elongate, distal three-quarters of each tooth occupied by sensillar field.
Genital operculum: Two opercular sclerites relatively wide, as long as pectinal plate, and completely separated (Figs 28B, 30).
Mesosoma: Pretergites surfaces almost smooth; post-tergites I– VI surfaces finely granular, acarinate (Figs 27A, 28A); sinistral dorsosubmedian and dorsolateral carinae of tergite VII visible (Fig. 27A). Sternites surfaces smooth, with scattered macrosetae; posterior margin of sternite I broadly recurved (Fig. 27B); respiratory spiracles (stigmata) not visible.
Metasoma: Segments I– IV progressively increasing in length, I wider than long, others longer than wide (Figs 27A, B, 28D, E). Segments I– IV lateral and ventral surfaces each with few, short macrosetae;dorsalsurfaceseachwithdistinctdepression.Segments I and II each with six distinct carinae (paired dorsosubmedian, dorsolateral, and ventrolateral carinae), III and IV each with eight distinct carinae (paired dorsosubmedian, dorsolateral, ventrolateral, and ventrosubmedian carinae); dorsosubmedian carinae distinct, crenulate, and converging posteriorly on segments I– IV; dorsolateral carinae distinct, slightly serrate on segments I– III, moderately serrate on IV; ventrolateral carinae distinct, slightly serrate on segments I– IV; ventrosubmedian carinae absent on segments I and II, obsolete on III and IV.
Remarks: The specimen examined possesses a relatively small pair of pectines, unlike the larger pectines of the holotype specimen, suggesting that it may be female.
Material examined: MYANMAR: Kachin State: Noije Bum near Hukawng Valley, precise locality unknown, Cretaceous (Cenomanian) burmite: one juv. [♀?], metasomal segment IV and telson absent (NIGP 200657).
description: Published as part of Xuan, Qiang, Prendini, Lorenzo, Engel, Michael S., Cai, Chenyang & Huang, Diying, 2025, Extinct scorpion family Chaerilobuthidae from Mid-Cretaceous Burmese amber reinterpreted as subfamily of extant family Pseudochactidae (Chelicerata: Scorpiones), pp. 1-60 in Zoological Journal of the Linnean Society 203 (1) on pages 34-39, DOI: 10.1093/zoolinnean/zlae169, http://zenodo.org/record/14831464