The Salticidae (Spiders) of Panama/Atelurius

by Arthur M. Chickering

Genus Atelurius Simon, 1901

Atelurius incertus Banks, 1929
Figures 214–218

Mr. Banks ('29) had a single female from the Canal Zone Biological Area, July 1924. Simon established the genus on the basis of a species from Venezuela, and thus far only two species have been referred to it. I am unacquainted with the genus and, from Simon's brief treatment of it, I am unable to come to any decision as to the correct placement of this species. The Peckhams had a species in their collection which they labelled Akela, new. This appears to be very close to A. incertus Banks. The Peckhams established the genus Akela on the species A. charlottae from Guatemala. I think the species under consideration here is not an Akela. I know nothing better to do with it for the present than to retain it here pending further knowledge.

Male allotype. Total length 3.20 mm. Carapace 1.50 mm. long, 1.20 mm. wide at level of PLE which occupy forty-eight fifty-thirds of the width of the carapace at their level; very little narrowed in front; fairly high; shaped much as in Zygoballus; slightly more than three quarters as high as wide; gently arched dorsally for nearly six sevenths of length to posterior declivity which is slightly concave and descends abruptly to posterior border (Fig. 214).

Eyes. Seen from in front, anterior row strongly recurved. Posterior row wider than anterior row in ratio of 49 : 45, middle row slightly narrower than anterior row. Quadrangle of laterals wider than long in ratio of 49 : 29. Total eye space occupies almost half the length of the carapace. Ratio of eyes AME : ALE : PME : PLE = 14 : 7 : 1.75 : 6. AME separated from one another by a little less than one fourteenth of their diameter, from ALE by nearly one seventh of their diameter. Eyes of second row equidistant from ALE and PLE. Height of clypeus equal to a little less than three fourteenths of the diameter of AME. A fairly conspicuous small tuft of white scale-like hairs projecting downward from beneath each AME.

Chelicerae. Robust, quite porrect, considerably produced; divergent beyond the basal third; with well developed basal boss; basal segment .80 mm. long; most of front surface covered by long white procumbent hairs, somewhat erect along dorsal edge. Fang fairly long and slender, slightly sinuous. Fang groove distinct, with a single robust retromarginal tooth near base of fang, and two promarginal teeth, one near base of fang and the other near medial end of groove.

Maxillae. Parallel; considerably dilated distally; quite concave along outer border; palp inserted into proximal half; longer than wide in middle in ratio of about 2 : 1; with well developed scopula along truncature and the usual serrula.

Lip. Widest at base where it is as wide as long; distal margin regularly convex; basal excavations reach less than one third of length of organ; sternal suture slightly procurved.

External Anatomy of Spiders

Fig. 210. Ashtabula dentata, female cheliceral teeth.
Fig. 211. A. dentata, epigynum, ventral view.
Fig. 212. A. montana Chickering; first leg.
Fig. 213. A. montana Chickering; epigynum, ventral view.
Fig. 214. Atelurius incertus, carapace, lateral view.
Figs. 215–216. A. incertus, male palp, ventral view; and retrolateral view.
Fig. 217. A. incertus, male abdomen, dorsal view.
Fig. 218. A. incertus, epigynum, ventral view.
Fig. 219. Beata levispina, carapace, lateral view.
Fig. 220. B. levispina, chelicera, front view.

Sternum. Longer than wide in ratio of 3 : 2; scutiform; widest between second coxae, but nearly as wide between first; quite convex; terminates posteriorly in a blunt point which is not extended between fourth coxae which are separated by three tenths of their diameter.

Legs. 1423. Tibial index of first and fourth legs 17.

	Femora	Patellae	Tibiae	Metatarsi	Tarsi	Totals
(measurements in mm)
1.	.96	.50	.70	.56	.38	3.10
2.	.77	.42	.48	.44	.33	2.44
3.	.77	.37	.48	.42	.36	2.40
4.	.97	.42	.63	.51	.38	2.91
Palp	.60	.22	.13	—	.42	1.37

Legs without fringes. First leg considerably extended and first femora somewhat enlarged but not greatly so.

Spines. First leg: femur dorsal 0-0-1-1-1, prolateral distal 2; patella only prolateral 0-1-0; tibia only prolateral 0-1-0, ventral 1r-1r-2 on right, 1r-2-2 on left; metatarsus only ventral 2-2. Second leg: as in first except metatarsus ventral 1r-2. Third leg: femur dorsal 0-1-1-1, prolateral and retrolateral distal 1; patella only retrolateral 0-1-0; tibia only prolateral 0-1-0; retrolateral 0-2-0, ventral 0-0-2; metatarsus prolateral 0-0-2, retrolateral 0-0-1, ventral 0-0-2. Fourth leg: femur and patella as in third; tibia prolateral 0-1-0, retrolateral 0-1-0, ventral 0-0-2; metatarsus as in third.

Palp. Both tibia and patella short with former only a little more than half as long as latter; femur much bent; tibial retrolateral apophysis long, slender, and sinuous; embolus sickle-shaped from an expanded base (Figs. 215–216). At distal end of femur is a dorsal snow white cap of scales which may extend over a much longer part of the segment in life.

Abdomen. Ovoid, longer than wide in ratio of 13 : 8; widest near middle; all spinnerets short, first pair most robust, third pair somewhat slender and plainly two-jointed, middle pair shortest and closely surrounded by others; tracheal spiracle near base of spinnerets; apparently colulus indicated by a very small tuft of black bristles.

Color in alcohol. Legs: first and second pairs of coxae dull brownish, others lighter; all femora dark brown with scattered white scales, first pair with a rather conspicuous prolateral white patch of scales; all patellae yellowish tipped with reddish brown; all tibiae reddish brown; first metatarsi yellowish in proximal third, elsewhere reddish brown, second and third metatarsi yellowish except reddish brown distal ends, fourth metatarsi entirely reddish brown; first three pairs of tarsi yellowish, fourth pair reddish brown with yellowish tips. Carapace: rich reddish brown, almost black around eyes; a broken white stripe extends on each side from ALE to posterolateral corner and down to posterior border; a few white scales along ventral margin; central part of clypeus between AME without whitw scales which extend as a tuft beneath AME and over front surface of chelicerae and, less conspicuously, laterally along cheek region. Abdomen: dark reddish brown at base; then a series of light and dark bars on dorsum best shown in Figure 217; thus nine distinct dorsolateral bars; venter dull brown.

Female. Characters briefly summarized by Banks ('29). Epigynum with a deep central posterior marginal notch and a median swelling separating two shallow cavities (Fig. 218).

Type locality. Male allotype from Canal Zone Biological Area, June, 1939. Male paratypes and females from the following localities: El Valle, R. P., July 1936; Canal Zone Forest Reserve, C. Z., July–Aug., 1939; Canal Zone Biological Area, June, Aug., 1939.