Ancylometes Bertkau
Creators: name: Höfer, H.
name: Brescovit, A. D.
Publisher: name: Zenodo
Year: 2000
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Ctenidae
Ancylometes

description: Genus Ancylometes Bertkau, 1880
Ancylometes Bertkau, 1880: 114. Type species by monotypy: Ancylometes vulpes Bertkau, 1880.
Lycoctenus Pickard-Cambridge, 1897: 95. Type species: Ctenus bogotensis Keyserling (= A. bogotensis).
Corinoctenus Mello-Leitão, 1939: 139. Type species: Corinoctenus anomalostomus Carcavallo & Martinez (= A. concolor).
Diagnostic characters. - Large spiders (up to 40 mm long) differing from other genera by the presence of 1-16 short ventral spines on tarsi III and IV in both sexes (a putative synapomorphy for the species of the genus) and the genital characters: Male palps with a basally broad, semicircular filiform embolus, attached fixedly retrolaterally to tegulum. Soon after the origin the embolus is flanked by a membranous lobe, which is species-specific in its form. In its filiform part the embolus is embedded in a wing-shaped conductor. Opposite to the conductor a characteristic hook- or hammer-like median apophysis (unca in Merrett 1988). Female epigyne with a central plate in form of a bike saddle with its nose pointing posteriorly, varying from nearly circular over drop-shaped and triangular to rectangular, flanked by broad lateral plates. Males always present broad white (in one case obscured) marginal bands on cephalothorax. The egg-sacs, carried by the females with their chelicerae and palps are subspherical and receive a thick layer of purplish-brown, hard silk on the ventral side (egg-sacs of Thalassius, Ctenus and Phoneutria are white).
Description. - Large ecribellate hunting spiders, total body length of 15-40 mm. Prosoma oval to pear-shaped in dorsal view, 1.2 to 1.4 times longer than wide, dome shaped, height approximately 1/5 of prosoma length, cephalic area not elevated, fovea linear, shallow. Ocular area narrow, eye formula ctenoid: 2-4-2, both eye rows strongly recurved, ocular quadrangle about as long as broad behind, scarcely narrower in front, all eyes round except anterior lateral eyes. Clypeus moderately high, less than twice AME diameter. Integument uniformly brown, body and legs densely covered by hairs. Colour patterns formed by dense cover of yellow, purpurish or white hairs. Ventral parts usually lighter. Males usually lighter than females, and with the exception of A. terrenus, where prosoma is bright purpurish to golden brown (Pl-Fig. 2), all males present broad white to yellow marginal bands (Pl-Fig. 1; like Dolomedes). Abdomen with 1-3 pairs of muscle spots (not visible in very dark specimens). Chelicerae stout with large boss, at base covered by long hairs (often white). Retromargin of fang furrow with 4 or 3 stout teeth, third sometimes considerably smaller, promargin with 1 large (median) and 1 or 2 small teeth. Sternum subcircular, labium without basal notch, length about 1.5 times width. Legs long, leg formula 4123, trochanters weakly notched. Slight sexual dimorphism in length and spination of legs. Males smaller with relatively longer legs, ratio of total length of leg IV to prosoma length 4.2-5.2 in males, and 3.7-4.0 in females. Femora of legs and palpi with dorsal and lateral spines. Males with 1 pro- and 1 retrolateral spine on all patellae, females only on patellae III and IV. Tibia I and II ventrally with 4, tibia II and IV with 3 pairs of short spines, no dorsal or lateral spines on tibia I and II in females (eventually 1 short prolateral); 2 prolateral, 2 or 3 retrolateral and 2 or 3 dorsal spines on all tibiae in males and tibia III-IV in females. Metatarsi I and II ventrally with 4-7 spines, males with 3 prolateral and 3 retrolateral spines and no dorsal spines (eventually 2 small dorsal apical ones). Metatarsi III and IV ventrally with paired apical spines and up to 10 single spines, 3-5 prolateral, 3-4 retrolateral and 3-6 dorsal spines. Male and female tarsi III and IV ventrally with 1-16 short spines, hidden by dense scopulae (Fig. 1). Spination of palps in both sexes equal (except tarsi): femora with 4-6 dorsal and 1 pro- and 1 retrolateral spines, patella with 1 prolateral and tibia with 2 pro- and 1 retrolateral spines; tarsus in females with 2 or 3 pro- and 1 or 2 retrolateral spines, in males 0-2 lateral spines.
Paired tarsal claws pectinate, unpaired claw small, obscured by dense scopulae (Fig. 2). Claw tufts absent. Trichobothrial pattern: single large, curved trichobothria apically on all patellae, two rows of trichobothria on tibiae and metatarsi, increasing in length from base to apex, trichobothrial base with transversely striated hood (Fig. 3).
Anterior lateral spinnerets (ALS) two-segmented with truncated distal article, bearing two major ampullate gland spigots near inner margin and approximately 80-100 piriform gland spigots on flattened base in females and 70-90 piriform gland spigots in males (Fig. 16). Posterior median spinnerets(PMS) unisegmented, nearly same size as ALS. PMS spinnerets of females bear 2 minor ampullate gland spigots on inner margin and approximately50 cylindrical gland spigots with elongated shafts (Fig. 17). PMS of males lack cylindrical gland spigots but bear two minor ampullate tartiporous gland spigots and approximately30 aciniform gland spigots. Posterior lateral spinnerets (PLS) two-segmented, longer and narrower than ALS and PMS. Distal article one third of whole spinneret, bearing 100-120 aciniform gland spigots in females and approximately 80 in males. Colulus small, globular and strongly covered by hairs.
Male palpal tibia with ventral short, curved apophysis and larger retrolateral apophysis (Fig. 5, 28). Embolus broad at base and flanked by transparent membranous lobe (Fig. 5, 8, 12, 18, 24) in its further course filiform, embedded in wing-like conductor (Fig. 5, 7, 8, 12, 18, 24). Opposite to conductor very characteristic hammer-like median apophysis (Fig. 5, 8, 12, 18, 24). Female epigynum with species-specific median plate with general form of bike saddle: narrow rounded triangle (Fig. 10, 15), broad rectangular (Fig. 6), nearly circular (Fig. 42), broad triangular (Fig. 23, 50, 52) or narrow rectangular (Fig. 21, 45) with or without (Fig. 10, 42) median protuberance or cavity. Median plate flanked by broad lateral plates. Vulva: pair of simple, large (sub)spherical spermathecae with pores (Fig. 11) without any recognizable stalks. Copulatory openings situated antero-laterally or laterally where anterior edges of lateral plates meet central plate, thus broad copulatory ducts start antero-laterally or laterally and reach spermathecae from ventral interiorly. Spermathecal ducts narrow, short, originating also ventrally from spermathecae behind entrance of copulatory ducts (posterior-interiorly; Fig. 11, 30). Females carry subspherical brown egg sacs in palps and chelicerae and construct large irregular nursery webs.
Composition. - Ten valid species plus one doubtful: Ancylometes birabeni (Carcavallo & Martinez, 1961: 9, fig. 3, female; not examined), described in Corinoctenus, new combination by Brignoli (1983: 462).
Distribution. - Tropical to subtropical Central and South America (Fig. 59), from El Salvador and Honduras (A. bogotensis) south to northern Argentina (A. concolor). Highest species diversity in the central Amazonian region (6 species). Specimens morphologically characterized as A. rufus from the coastal area of São Paulo with distinctly smaller specimens, might represent the southernmost population of an ancient brazilian rainforest-wide distribution (Amazonian-Atlantic Rain Forest) of this species.
description: Published as part of Höfer, H. & Brescovit, A. D., 2000, A revision of the Neotropical spider genus Ancylometes Bertkau (Araneae: Pisauridae), pp. 323-360 in Insect Systematics & Evolution 31 on pages 327-355