A cladistic analysis of the Stygnicranainae Roewer, 1913 (Arachnida, Opiliones, Cranaidae) - where do longipalp cranaids belong?

Abstract

A character survey compiling the morphological information of the subfamily Stygnicranainae was carried out. Two new species of Stygnicranaus Roewer, 1913 are described from Colombia and the new genus Agathocranaus is described from Ecuador. All known species of the subfamily are included in a matrix of 46 morphological characters. Parsimony analysis under implied weights recovered a monophyletic Stygnicranainae including Tryferos Roewer, 1931 plus Stygnicranaus and Agathocranaus. However, the usage of the four subfamilies of Cranaidae as currently defined is abandoned because the two largest subfamilies of Cranaidae -Cranainae and Prostygninae -represent paraphyletic groups (grades), whereas Heterocranainae is a superfluous subfamily, including only the genus Heterocranaus Roewer, 1913.

The poorly known genus Ventrifurca Roewer, 1913 revisited (Opiliones: Cranaidae)

“…But a more slender, sexually dimorphic pedipalpus, slightly elongate in males of V. albipustulata, hints to some relationship with the three genera of 'longipalp cranaids' which are thought to constitute a clade (see illustrations of all in Orrico and Kury 2009). In Tryferos, the pedipalpus of the male is immensely elongate (femur to tibia) and femur unarmed while the female has regular podomeres.…”

“…Its taxonomy is unsatisfactory and plagued by many monotypic and poorly known genera. The monophyly of this taxon has been recovered in some phylogenetic studies (Orrico and Kury 2009;Sharma and Giribet 2011;Pinto-da-Rocha et al 2014). Nevertheless, a molecular study by Pinto-da-Rocha et al (2014) considered it as a member of the Gonyleptidae.…”

“…It is currently difficult to find any pattern of distribution of the genera in this family due to (1) the unsatisfactory taxonomy with many monotypic/meaningless genera, (2) species known from only one locality, and (3) poorly studied collections in the Andean region. A few comments can be made on two monophyletic groups: (1) the 'longipalp cranaids' (formerly Stygnicranainae) which are distributed in the south of Colombia and north of Ecuador associated to Northwestern Andean montane forests (Orrico and Kury 2009) and (2) the genus Phareicranaus which has some species groups (Villarreal, unpublished data), one of them associated to north of south America (Venezuela, Panama and Trinidad) and another well distributed in the Amazonian Basin (Brazil, Ecuador, Peru). Although only three species of Ventrifurca are known, this could be a more diverse genus and seems to be restricted to the western range of the Colombian Andes and Ecuador, from north of Ecuador about 700 km north into northwestern Colombia.…”

“…Nevertheless, a molecular study by Pinto-da-Rocha et al (2014) considered it as a member of the Gonyleptidae. However, because Orrico and Kury (2009) found that of the four traditional subfamilies of cranaids, two are microdiverse and the other two are paraphyletic, they proposed to abandon the use of subfamilies at least as currently defined. On the other hand, Kury (2012b) proposed the inclusion of Zamorinae as a fifth subfamily wich, posteriorly was transferred to Nomoclastidae by Kury & Villarreal (2015).…”

“…Recently, some works have been published addressing varied taxonomy and systematic issues in the family, primarily three systematic works, two papers focusing on the relationship of the genus Phareicranaus Roewer, 1913 (Pinto-da-Rocha andKury 2003;Pinto-da-Rocha and Bonaldo 2011) and another focused on testing the monophyly of Stygnicranainae (Orrico and Kury 2009). Subsequently, some contributions on the alpha taxonomy of Cranaidae were published, either as (1) transfer of taxa from other families to Cranaidae (Pinto-daRocha and Hara 2009;Pinto-da-Rocha et al 2012), (2) description of new taxa (Kury 2012a, b), (3) detection of 'false cranaids' (Villarreal and Kury 2012), or (4) synonymy or revalidation and redescription of some genera (Hara et al 2014).…”