Cryptic Bark Crab Spiders

Isala L. Koch, 1876

Type species: Isala punctata L. Koch, 1876

Fauna Portal Genus Number: 3115

(after Machado & Teixeira 2021): Species of Isala resemble those of Borboropactus by their cryptic behaviour, with individuals frequently presenting lichen, sand and other soil particles attached to their tegument, and by the elongated body shape: prosoma and opisthosoma longer than wide, and anterior legs (I and II) aligning parallel to each other and directing frontwards. However, males of Isala can be recognized and distinguished by their well-developed palpi with cymbial projection, long and curved retrolateral tibila apophysis and filiform embolus, lacking the median apophysis and the conductor, observed for Borboropactus. Females of this latter have acute lateral projections on the epigynal plate, known as “epigynal teeth”, while females of Isala present a flattened atrium and folds of the epigynal plate strongly sclerotized, forming almost like “pockets” that protect and hide the copulatory ducts (in ventral view). Moreover, the ocular arrangement in Isala is characterized by the anterior lateral eyes noticeably bigger than the anterior median eyes and the anterior eye row strongly recurved, while in Borboropactus the anterior eyes are all similar in size and arranged in a straight row.