Bioacoustics of Craspedisia cornuta

Description . Male (IBSP 215592). Coloration of specimen still dead in alcohol: dorsally orange carapace with distal cephalic black area ( Fig. 1 A−B), ventrally with endites, labium and sternum greyish. Legs with yellowish coxae, trochanters and base of femurs, remaining dark gray ( Fig. 1D ). Abdomen gray with four rounded dorsal black spots and ventrally gray ( Fig.1A ). Carapace oval, covered with long hairs on prosomal pits and excavated base, thoracic groove deep and transversal, in the posterior third, posteriorly with large and stridulatory plate subrectangular, covering the pedicel, with more than 50 longitudinal grooves on the plate. Eyes in a projected cephalic area ( Fig. 1B ), with median anterior eyes slightly larger than the others ( Figs 2 A−B, G−H). Proboscis thick, fingerlike, curved down, covered with long bristles throughout, inserted in the median region of the clypeus, below the AME, of which it is separated by a diameter ( Figs. 2 B−F). Clypeus projected on the chelicerae, with differentiated border and split in the median region ( Fig. 2D, F ). Chelicerae with three teeth on anterior margin (one teeth in Levi, 1963 ) ( Fig. 3A ). Endites truncated, with serrula presenting almost 30 small teeth in a row. Labium rounded, fused to sternum. Sternum tuberculate, covered with long hairs ( Fig. 3B ). Slender legs, with three claws, anterior with six ventral teeth, median elongated, smooth and curved, and false claws represented by 3−5 hairs ( Fig. 3C ); trichoboth- ria with rounded base, circular aperture and long hair ( Fig. 3D ), distributed in two rows on the dorsal area of legs I–IV; tarsal organ rounded, smooth with circular aperture ( Fig. 3 G−H) and chemosensitive setae as in female. Abdo- men with large ventral plate, which ends before the spinnerets, furrowed in the posterior third, where it houses two furrowed areas, where are the epiandric fusules ( Figs 3E , legs; 3F, cymbium). Colulus small and triangular ( Fig. 3F ). Male palp: short tibiae, enlarged distally with elongate setae, and a dorsal basal, rounded trichobothria ( Figs. 4 A−B). Cymbium oval, with Theridiid cymbial hook elongated ( Fig. 4E, H ). Subtegulum canoe-shaped, supporting the tegulum and distal structures ( Figs 4C, E ) and presenting a globose retrolateral projection ( Fig. 4H ). Tegulum large, projected posteriorly and conic at tip, with tegular apophysis conical, behind the embolus ( Fig. 4 E−F); median apophysis originating behind the embolus, distally flattened; pedunculate conductor, with distal area flattened, supporting the tip of embolus; embolus thick, longitudinally sulcated, with large and subquadrate base, having convex striations in the median area, ( Figs 4 C−H). Female . Coloration (from IBSP 215592) as in male, except distal area of tibia and metatarsus I–II darker and abdomen black, with small black spots; and epigynal plate orange as the anterior and lateral plates ( Fig. 1 D−F).. Carapace covered with less long hairs on prosomal pits and concentered in the cephalic area, stridulatory plate subrectangular, with less longitudinal grooves on the plate that the male ( Figs 5 A−C). Clypeus and eyes ( Fig. 5C ) as in male, proboscis absent ( Fig. 1D ). Chelicerae short, with two teeth on anterior margin ( Fig. 5D ). Endites, serrula and sternum as in male ( Figs 5 E−G). Labium largest the male, fused to sternum ( Fig. 5E ). Legs as in males, with three claws, anterior hairs and false claws of the legs I–II not impregnated with possible sap of plant material ( Fig. 6F ) and posteriors legs III–IV with hairs and false claws covered by this material ( Fig. 6 D−E). Trichobothria with rounded base, circular aperture and long hair ( Fig. 6A ), distributed in the leg as in male ( Fig. 6 A−B); tarsal organ capsuled, smooth with circular aperture ( Fig. 5H ) and chemosensitive setae smooth and elongated ( Fig. 6C ). Abdomen with ventral plate lesser than male, circular anteriorly and having laterally with a group of hard spines, probably to rub in the stridulatory plate ( Fig 7 A−C). Colulus oval and elongated at tip ( Fig. 7D ). Epigynum with ventral plate larger than long, subrectangular ( Fig. 7E ) or semicircular ( Fig. 7F ), with ample anterior opening. Internally with globose spermathecae, short copulatory ducts united at base, elongated fertilizations ducts and large inner area of the atrium ( Fig. 8 A−B; see Levi, 1963 , fig. 28). Natural History. Craspedisia cornuta individuals are found in tree trunks of Piptadenhia gonoacantha (Mart.) JF Macbr. ( Fabaceae ), Croton floribundus Spreng. (Euphorbiaceae) , and Zanthoxylum rhoifolium Lam. (Rutaceae) in ranges ranging from 0.5m– 1.7 m height (n = 55) in forest areas. Its distribution in the trunks is not random, occurring more frequently in places where there are shelter structures such as loose bark or protuberances and moss coverings along the trunk, which act as a rain protection roof ( Fig. 9A, F ). The webs are star shaped with anterior aperture ( Fig. 9 B−D). The web is slightly inclined from the base towards the shelter ( Fig. 2A ). Craspedisia cornuta has nocturnal habits, remaining in this period in the trunk, outside the web. During the day, they are sheltered in the back part of the web ( Fig. 9E ). The webs are usually found in lichen and moss-lined trunks ( Fig. 9 ). Adult individuals were found mainly in the summer, in the months of December and January ( Fig. 10 ), a period of higher rainfall where lichens and mosses are lush. According to Paquin & Dupérré (2001) , the reproductive period of a spider species population is determined by the peak abundance of adult males. Thus we understand that the population of C. cornuta presents a spring and summer stenochronic phenological pattern with a very marked period of activity of adult spiders in a defined period of the year—according to the classifications of Tretzel (1954) and Paquin & Dupérré (2001) . This phenological pattern where sexually active males are available for a few months has also been recorded in other spider populations in the temperate ( Merrett 1967 ) and Neotropical regions ( Villanueva-Bonilla & Vasconcellos-Neto 2016 ; Villanueva-Bonilla et al. 2018 ). In the case of autumn 2016, some remaining adult females from the previous summer were still found ( Fig. 10 ), probably individuals who had less pressure for predators or fluctuating climatic conditions in the region. One aspect that caught our eye when examining SEM images of the nails of the legs was the presence of a hardened substance covering the false claws and distal bristles to the legs. These characteristics were observed only in the legs III−IV of the females ( Fig. 5 D−E), being absent in the legs I−II ( Fig. 5F ), as well as in the legs of the males where we did not observe these inlays ( Fig. 2C ). We suspect that the substance could be sap of lichens or mosses, where females usually build their refuges and remain largely hidden.