History:

The genus Eucratoscelus was established in 1898 by Reginald Innes POCOCK on the base of a femle E. longiceps. In 1873 described the german professor Dr. Carl Eduard Adolf GERSTÄCKER (*1828 - †1895), 25 years afore POCOCK, the species Harpactira constricta, a synonym of E. longiceps, which was later synonymised in 2002 with E. constrictus by Richard C. GALLON. The habit of the holotype is Taveta in southern Kenya, which is on the border to Tanzania.
The genus was up to 1990 monotypical, then Dr. Günther SCHMIDT and Volker VON WIRTH described the female of E. pachypus which exact habit is unkonwn. 12 years later in 2002 GALLON described the male of E. pachypus which looks totally different in comparison with the female.
The area of circulation is Kenya and Tansania.

Key features of the genus:

strongly incrassate Tibia IV (viewed dorsally) (Fig. 71 , 79 )
Scopulae on the chelicerae retrolateral present (s. P. chordatus )
Scopulae on the chelicerae prolateral absent (s. P. lugardi )
Typical Harpactirinae abdominal pattern absent/weakly-developed
Fovea transverse
medium-sized Harpactirinae (female: ~40mm, male: ~25mm)
Distal segment of posterior spinneret digitiform (Fig. 108 )
Tarsal scopulae undivided (s. P. chordatus )
Metatarsal scopulae on leg I, II and III undivided (s. P. chordatus )
Metatarsal scopulae on leg IV bisected longitudinally by band of stiffened setae (s. P. chordatus )
Spermathecae paired, with terminal lobs (Fig. 73 , 74 , 81 , 82 )

Species:

Eucratoscelus constrictus (GERSTÄCKER, 1873) (Type species)

	Distribution: Kenya Coloration: (in Alcohol) Legs, palpi, abdomen and carapace grey/ash. Leg IV with few, long stiffened, setae on retrolateral surfaces of patella and tibia (Fig. 71 ). Leg and palp joints are pale yellow. Abdomen yellow/brown with sparse, long, emergent setae. Dorsum of Abdomen without dark pattern of bars, spots or reticulations. Venter of abdomen yellow/brown. Sternum and coxa dark. Fovea: deep, transverse Spermathecae: with single rounded terminal lobs. Main body of spermathecae sub-triangular in form. (Fig. 73 , 74 ) Palpal bulb: pyriform, with very fine, strongly curved, acuminate embolus. Keels absent along embolus (Fig. 69 ). Body length: male ~25mm, female ~40mm

Eucratoscelus pachypus SCHMIDT & VON WIRTH, 1990

	Distribution: Tanzania and probably Kenya Coloration: Legs I-III and palpi grey/ash. Leg IV dark brown with numerous, long, stiffened russet setae on retrolateral surfaces of patella, tibia, metatarsus and tarsus (s. Photo ). Leg and palp joints are pale yellow. Carapace grey/ash without radial striae; dark "mask" around ocular tubercle. Dorsum of abdomen dark brown with sparse, long, emergent, orange/brown setae. Dark pattern of bars, spots or reticulations rarely visible on abdomen. Venter of abdomen grey/ash with pale orange booklung covers. (only subadult and adult males have a dark band along the abdomen) Sternum and coxa black. Fovea: deep, transverse Spermathek: with single rounded terminal lobs. Main body of spermathecae sub-triangular in form (Fig. 81 , 82 ). Palpal bulb: pyriform, with very fine, curved, acuminate embolus. Keels absent along embolus (Fig. 75 , 76 , 77 ). Body length: male ~25mm, female ~45mm

Synonyms:

E. longiceps POCOCK, 1898 = E. constrictus (GERSTÄCKER, 1873)

E. tenuitibialis Schmidt & Gelling, 2000 = Pterinochilus lugardi POCOCK, 1900

Harpactira constricta GERSTÄCKER, 1873 = E. constrictus (GERSTÄCKER, 1873)
Pterinochilus spinifer POCOCK, 1898 = E. constrictus (GERSTÄCKER, 1873)