Jairo A. Moreno-González

The enigmatic monotypic genus Timesius Simon, 1879, hitherto assigned to Stygnidae Simon, 1879, is redescribed and its phylogenetic position inferred upon morphological and molecular evidence, resulting in its reallocation to the family Nomoclastidae Roewer, 1943. The type material of Timesius vesicularis (Gervais, 1844), long presumed lost, was rediscovered, and is hereby redescribed and illustrated. Also, a new species, Timesius paramuno sp. nov., is described based on specimens collected in the Páramo ecosystem in the Central Cordillera, Colombia. Timesius vesicularis can be readily distinguished by having two long spines on area III of the dorsal scutum (two short tubercles in T. paramuno sp. nov.) and small whitish-yellow granules on the ocularium and dorsal scutum (vestigial whitish-yellow granules in T. paramuno sp. nov.).

Background/Objectives: Arachnids are a megadiverse arthropod group. The present study investigated the chromosomes of pedipalpid tetrapulmonates (orders Amblypygi, Thelyphonida, Schizomida) and two arachnid orders of uncertain phylogenetic placement, Ricinulei and Solifugae, to reconstruct their karyotype evolution. Except for amblypygids, the cytogenetics of these arachnid orders was almost unknown prior to the present study. Methods: Chromosomes were investigated using methods of standard (Giemsa-stained preparations, banding techniques) and molecular cytogenetics (fluorescence in situ hybridization, comparative genomic hybridization). Results and Conclusions: New data for 38 species, combined with previously published data, suggest that ancestral arachnids possessed low to moderate 2n (22–40), monocentric chromosomes, one nucleolus organizer region (NOR), low levels of heterochromatin and recombinations, and no or homomorphic sex chromosomes. Karyotypes of Pedipalpi and Solifugae diversified via centric fusions, pericentric inversions, and changes in the pattern of NORs and, in solifuges, also through tandem fusions. Some solifuges display an enormous amount of constitutive heterochromatin and high NOR number. It is hypothesized that the common ancestor of amblypygids, thelyphonids, and spiders exhibited a homomorphic XY system, and that telomeric heterochromatin and NORs were involved in the evolution of amblypygid sex chromosomes. The new findings support the Cephalosomata clade (acariforms, palpigrades, and solifuges). Hypotheses concerning the origin of acariform holocentric chromosomes are presented. Unlike current phylogenetic hypotheses, the results suggest a sister relationship between Schizomida and a clade comprising other tetrapulmonates as well as a polyploidization in the common ancestor of the clade comprising Araneae, Amblypygi, and Thelyphonida.

A new genus and species of short-tailed whipscorpion (Schizomida: Hubbardiidae Cook, 1899) is described based on specimens collected in the Venezuelan state of Amazonas. The new genus differs from other Neotropical genera in the presence of six setae on opisthosomal tergite II, the absence of seta Dm4 on the flagellum in both sexes, the female flagellum comprising four segments, and the median lobes of the spermatheca being four times longer than the lateral lobes. Jipai longevus gen. et sp. nov. increases the count of South American schizomid genera to fourteen and the count of species to 57. The type locality of the new taxon is situated in the Guiana region of Amazonia s. l., where three other hubbardiid genera have also been recorded. This discovery contributes to the understanding of Amazonian schizomid diversity and highlights the need for further sampling in this diverse, vulnerable and poorly explored area.

Thelyphonida Blanchard, 1852, also known as vinegaroons or whip-scorpions, is a small arachnid order with 140 described species contained in a single family, Thelyphonidae Lucas, 1835. Despite being conspicuous and widely distributed across the tropics and subtropics on four continents, knowledge of the order has been slow to advance. Hypoctoninae Pocock, 1899, one of four subfamilies currently recognized and one of two represented in the New World, comprises five genera. Since its inception, Thelyphonellus Pocock, 1894 has remained the only hypoctonine genus occurring in South America, with only four species described prior to the present contribution. The first detailed morphological study and phylogenetic analysis of Thelyphonellus is presented herein. The morphological phylogenetic analysis—the first for Thelyphonida—includes all except one of the previously described species of Thelyphonellus in addition to two new species described herein; the species of Ravilops Víquez and Armas, 2005 (from the Caribbean island of Hispaniola); and the monotypic Old World genus Etienneus Heurtault, 1984 (from West Africa) scored for 45 morphological characters. A single, most parsimonious phylogenetic hypothesis revealed that Thelyphonellus is paraphyletic with respect to Ravilops. The New World Hypoctoninae comprises four clades with disjunct distributions and well supported by a combination of morphological characteristics, on the basis of which four genera, two of which are new, are recognized: Ravilops, with two species, endemic to Hispaniola; Thelyphonellus, herein restricted to Thelyphonellus amazonicus (Butler, 1872) and Thelyphonellus ruschii Weygoldt, 1979, occurring in Guyana, Suriname, French Guiana, and northern Brazil; Wounaan, gen. n., containing Wounaan vanegasae (Giupponi and Vasconcelos, 2008), comb. n. and Wounaan yarigui, sp. n. from Colombia; and Yekuana, gen. n., containing Yekuana venezolensis (Haupt, 2009), comb. n. and Yekuana wanadi, sp. n. from Venezuela. The two new species are described and illustrated. A key to the identification of the Neotropical genera of Hypoctoninae and a map plotting the known distribution of its species are also presented.

Sur l'un des plus petits scorpions amazoniens: une nouvelle espèce de Microtityus Kjellesvig-Waering, 1966 (Scorpiones, Buthidae) du Brésil, avec une diagnose amendée et une analyse de la distribution potentielle du genre. Une nouvelle espèce de scorpion, Microtityus adriki n. sp., est décrite sur la base de spécimens adultes collectés à Cantá, dans l′État de Roraima (RR), dans le nord du Brésil. Microtityus adriki n. sp. est la deuxième espèce de Microtityus Kjellesvig-Waering, 1966 connue au Brésil et constitue l′une des plus petites espèces de scorpions (12,39 à 19,47 mm) de la région amazonienne. Dans cette étude, nous proposons une diagnose générique amendée et une diagnose spécifique, décrivons l′hémispermatophore mâle de Microtityus, proposons la séquence de code-barres COI et une analyse de la distribution potentielle pour le genre. La morphologie de l′hémi-spermatophore mâle de Microtityus diffère de celle d′autres genres de buthidés néotropicaux, sauf pour le nombre de lobes (trois lobes), état de caractère partagé avec plusieurs genres. Le modèle de distribution potentielle généré par MaxEnt suggère une forte adéquation environnementale pour le genre dans les Antilles et le nord de l′Amérique du Sud, avec une adéquation élevée dispersée dans plusieurs régions d′Amérique centrale. Cependant, le modèle n′indique pas une adéquation élevée dans les zones où les espèces brésiliennes sont présentes (c′est-à-dire, Microtityus adriki n. sp. et Microtityus vanzolinii Lourenço & Eickstedt, 1983), ce qui pourrait s′expliquer par un biais d′échantillonnage. Par conséquent, des études futures, comprenant un échantillonnage approfondi, sont nécessaires pour mieux comprendre les processus biogéographiques à l′œuvre dans la distribution de ce genre.

The troglomorphic scorpion genus Troglotayosicus Lourenço, 1981, occurs in hypogean and epigean habitats in the Andean and Amazonian rainforests of Colombia and Ecuador. The phylogenetic relationships among the species of Troglotayosicus are currently unknown. In the present contribution, a new species, Troglotayosicus akaido, sp. nov., is described from specimens collected in the leaf litter of a primary rainforest in the Colombian Amazon, near the border with Peru, raising the number of species in the genus to seven. The new species represents the easternmost record of the genus and further extends its distribution into the Amazon. Its phylogenetic position was tested in an analysis of all species of the genus and two outgroup taxa, scored for 131 morphological characters (16 new and 115 legacy; 104 binary and 27 multistate) analyzed with maximum likelihood under the MK model. Troglotayosicus was recovered as monophyletic and composed of two main clades. The morphological survey revealed that the ventral macrosetae of the leg telotarsi of the type species, Troglotayosicus vachoni Lourenço, 1981, are simple, subspiniform macrosetae, irregularly distributed, but not arranged into clusters nor forming elongated clusters of setae/spinules, as previously suggested. A distribution map and key to the identification of the species of Troglotayosicus are provided. Further research, incorporating molecular data, is needed to understand the evolution and biogeographical history of this enigmatic scorpion genus.

The ancient, enigmatic whip spider family Paracharontidae Weygoldt, 1996, representing the basalmost lineage of the arachnid order Amblypygi Thorell, 1883, is revised. The monotypic West African genus Paracharon Hansen, 1921, from Guinea Bissau, is redescribed, based on a reexamination and reinterpretation of the newly designated lectotype. A new troglobitic whip spider, Jorottui ipuanai, gen. et sp. nov., is described from a cave system in the upper basin of the Camarones River in the La Guajira Department of northeastern Colombia. This new taxon is the second extant representative of Paracharontidae and the first outside Africa. It is unambiguously assigned to the family based on several characters shared with Paracharon caecus Hansen, 1921, notably a projection of the anterior carapace margin, the tritosternum not projecting anteriorly, similar pedipalp spination, a reduced number of trichobothria on the tibia of leg IV, and cushionlike female gonopods. A detailed examination confirmed the absence of ocelli in both genera and the presence of three (Paracharon) vs. four (Jorottui, gen. nov.) prolateral teeth on the basal segment of the chelicera, the dorsalmost tooth bicuspid in both genera. The male gonopods of Paracharontidae are described for the first time. Paracharonopsis cambayensis Engel and Grimaldi, 2014, is removed from Paracharontidae and placed incertae sedis in Euamblypygi Weygoldt, 1996; amended, comparative diagnoses are presented for Paracharontidae and Paracharon; and previous interpretations of various diagnostic characters for Paracharontidae are discussed.

The widely distributed species, Stenochrus portoricensis Chamberlin, 1922, is recorded for the first time from Costa Rica and Venezuela, and new occurrences from Brazil and Colombia are presented. Morphology of spermathecae from 14 localities is compared and illustrated. The need for studies to evaluate the potential status as an invasive species of S. portoricensis is commented on and a distribution map of the species in southern Central America and South America is given.

The Tityus forcipula species group has had an intricate taxonomic history, changing its diagnostic characters and composition on several occasions. One of the alleged reasons for this taxonomic uncertainty is the use of superficial characters (i.e. raw similarity instead of putative synapomorphies) for species group delimitation. Here, we conducted a thorough phenotypic survey across the Tityus forcipula species group, as currently delimited, including characters that had been suggested elsewhere as putative synapomorphies for delimiting lineages within Tityus. In doing so we also redescribe Tityus forcipula and describe a new species belonging to the Tityus forcipula species group: Tityus moralensis sp. nov. based on specimens from the Andean region of Valle del Cauca department, Colombia. The Tityus forcipula species group is here delimited to Andean species from Colombia and Ecuador that share strongly sclerotized and brown colored pectines, basal middle lamellae of female pectines dilated and suboval or ovoid shaped, basal plate of female pectines without glandular region and telotarsi with two ventrosubmedian rows (type II) of stout macrosetae (i.e., Tityus crassicauda, Tityus cuellari, Tityus forcipula, Tityus fuhrmanni and Tityus moralensis sp. nov). The new Tityus species is placed into a phylogenetic context with other buthid species using DNA sequences (COI and 28S). Finally, we provide a map with updated distributional records of the Tityus forcipula species group.