Dibolostethus sicarius Hoffman, 2009

Figs 3A, E, 4A–B, 5, 8–9

Dibolostethus sicarius Hoffman, 2009: 151, figs 1–11.

Diagnosis

Adult males of D. sicarius differ from those of D. kattani sp. nov. based on the lack of short, blunt projections on the sternite of the 5 th body ring, and from D. inopinatus sp. nov. and D. kattani sp. nov. based on the following combination of gonopodal characteristics: solenomere relatively straight until gently curving dorsally at apex, tip sinuous (Fig. 5A); prefemoral process slightly wider basally, expanded at midpoint and recurved, forming a cup-shaped depression before apex; apex with three lamellate flanges, best seen in anterior view (Fig. 5B).

Type material

Holotype ECUADOR • ♂; Los Rios Province [originally reported incorrectly as Pichinchi Province], Rio Palenque Science Center; [0.588° N, 79.362° W]; 21 Mar. 1977; J. Reiskind leg.; VMNH110810.

Paratypes ECUADOR • 2 ♀♀; same collection data as for holotype; VMNH110811, VMNH110812.

Description

Male (holotype, VMNH110810)

With characteristics typical for the genus. Coloration (preserved in 70% isopropanol): body rings light brown to caramel; antennae and head light yellow; legs light yellow; telson reddish, with posterior margin (= spinnerets region) yellowish. Head: epicranial macrosetae 2+2, interantennal macrosetae 1+1, frontal macrosetae 2+2. Sternites: 4 th body ring with two thin, blade-like acute projections, tips separated throughout, nearly translucent (Fig. 4A–B). Gonopod aperture on 7 th body ring oval, rim notably projecting above sternite (0.35 mm), with a deep U-shaped concavity (0.2 mm) on posterior margin.

GONOPODS (Fig. 5). Gonocoxae rounded, equivalent to about three quarters the length of the telopodite; dorsum of left and right gonocoxa with 2 and 3 (possible aberration) macrosetae, respectively. Solenomere long, slender, unbranched, apex falciform and partially enveloped by prefemoral process (Fig. 5, S). Prefemoral process: long (similar in length to solenomere), width subequal to solenomere, widening at halfway point with a medial knob before curving laterad into a cup-like structure; apex broad, with a series of lamellate flanges resembling a hammerhead shark in lateral view (Fig. 5, PfP).

BODY MEASUREMENTS (mm). Total length 24.8, width of 10 th body segment 1.98. Antennomere lengths (1–7): 0.38, 0.75, 0.85, 0.85, 0.85, 0.85, 0.25. Collum: length 0.5, width 1.4. Podomere lengths of 10 th body ring (1–7): 0.28, 0.55, 0.9, 0.34, 0.53, 0.95, 0.09. Gonopod aperture: length 0.50, width 0.78. Gonopod: length 0.99, width 0.86. Gonocoxae: length 0.63, width 0.36. Telopodite: length 0.98, width 0.31. Telson length 0.78.

Female (paratype, VMNH110811) Coloration (preserved in 70% isopropanol) as in male. Body larger and more robust than male. Similar to male in general body outline and somatic characters, except sternite of 4 th body ring without pair of acute projections, 4 th, 5 th, and 6 th podosterna elevated to a lesser degree, 4 th and 5 th pair of legs not modified, and tibia lacking acute ventro-apical projections.

BODY MEASUREMENTS (mm). Total length 30.95, width of 10 th body segment 2.6. Antennomere lengths (1–7): 0.38, 0.9, 0.93, 0.88, 0.85, 0.83, 0.23. Collum: length 1.0, width 1.7. Podomere lengths of 10 th body ring (1–7): 0.3, 0.53, 0.9, 0.38, 0.45, 0.98, 0.09. Vulvar aperture width 0.56. Posterior margin of vulvar rim: well sclerotized, U-shaped; width 0.13. Vulvae: small, unmodified, setose (Fig. 8); length 0.45, width 0.29. Valves symmetrical. External valve: lateral length 0.5, lateral height 0.44; dorsal length 0.39, dorsal width at midpoint 0.14. Operculum: length 0.06, width 0.21. Telson length 1.15.

Distribution

Herein restricted to the Los Rios Province, Ecuador (Fig. 9).