Variation of cleaning organ structures and setae of pedipalp tarsus in the family Phrynidae (Arachnida: Amblypygi).

The pedipalp tarsus of Amblypygi is used as a cleaning tool in grooming behavior and as a weapon in prey capture. The tarsus presents several structures with unknown functions that probably relate to both processes. The Amblypygi tarsus possesses a cleaning organ with two lines of projections and a group of setae distributed along the structure. We analyzed the morphological variation of the cleaning organ structures and the setae of the tarsus in species of the family Phrynidae using scanning electron microscopy (SEM). Additionally, we made histological sections to evaluate the sensory function of the structures. We found variation in the shape and size of the setae, projections and granular area of the cleaning organ; however, the observed differences do not allow for differentiation of taxonomic genera. The setae and projections of the cleaning organ have an internal structure similar to tip-pore sensilla. Externally, the setae are similar to the sensorial hairs in spiders and differ from the cleaning organ projections, which probably are modified setae. Mechanoreception function is evident in the setae, and is probable in projections of the cleaning organ; the evidence observed indicates that both structures may be considered as putative chemoreceptors.

Two new species of the whip-spider genus Heterophrynus (Arachnida: Amblypygi) with complementary information of four species.

The family Phrynidae has been mainly recorded from America, including the Antilles, and Heterophrynus is one of its genera endemic of South America and is mainly associated with Amazonian ecosystems. Currently, the genus has 16 valid species, but many original descriptions are ambiguous or incomplete. The more complete work about this genus only includes seven of the currently valid species, and in some cases, some characters useful for the species identification, were not described. This situation hampers the species recognition and the comparison among species to propose diagnosis accurate. Using characters from the male and female genitalia to improve the diagnosis, we present complementary descriptions for four species of Heterophrynus and describe two new species. We present details of morphologic variation, compare the pedipalp spines among the species, present actualized distributions, and for first time, we present a complete illustration of the male genital of eight species using SEM pictures.