Revision of the Elusive Harvestmen Genus Discocyrtulus Roewer, 1927 (Opiliones: Laniatores: Gonyleptidae): Investigating the Presumed Northeastern Brazilian Discocyrtus-Like Relatives

Posted by
  Revision of the Elusive Harvestmen Genus Discocyrtulus Roewer, 1927 (Opiliones: Laniatores: Gonyleptidae): Investigating the Presumed Northeastern Brazilian Discocyrtus-Like Relatives ABSTRACT A maximum parsimony analysis based on morphological characters (23 taxa; 98 characters; 1951 scorings) was conducted to test the monophyly of Discocyrtulus Roewer, 1927, and to assess its phylogenetic relationships within Gonyleptidae. The results recover the species currently assigned to Discocyrtulus as phylogenetically distant from Pachylinae sensu stricto and nested instead within Discocyrtus sensu stricto +, forming a clade together with Discocyrtus moraesianus Mello-Leitão, 1923. Accordingly, Discocyrtulus is removed from Pachylinae Sørensen, 1884, and left without subfamilial assignment. As a result, Discocyrtulus now comprises Discocyrtulus crenulatus (Roewer, 1913) comb. nov. , Discocyrtulus marginalis Roewer, 1929, and Discocyrtulus moraesianus (Mello-Leitão, 1923) comb. ...

An eyeless new species of Monoblemma Gertsch, 1941 (Araneae: Tetrablemmidae) from Venezuela, with a new record of the single-eyed Monoblemma unicum Gertsch, 1941 from the Dominican Republic

Posted by

 


An eyeless new species of Monoblemma Gertsch, 1941 (Araneae: Tetrablemmidae) from Venezuela, with a new record of the single-eyed Monoblemma unicum Gertsch, 1941 from the Dominican Republic

The genus Monoblemma Gertsch, 1941 was recently revised by Martínez (2025) and currently comprises four species, mainly distributed in the Caribbean (World Spider Catalog 2026). Species of the genus exhibit remarkable variation in eye number, ranging from completely eyeless forms, such as Monoblemma becki Brignoli, 1978, to a single-eyed condition, with the eye positioned at the margin of the clypeal declivity in M. unicum Gertsch, 1941, and to four-eyed species, such as M. cambridgei (Bryant, 1940) and M. cubaense Martínez, 2025. In the original description of M. unicum, Gertsch (1941) noted that, because only a single specimen was available, the presence of one median eye might represent an abnormal condition. However, he also suggested that its median position and apparently normal development indicated that it was likely a constant feature of the species, probably resulting from the fusion of the anterior eyes present in species with two or four eyes. The discovery of a second specimen of Monoblemma unicum from the Dominican Republic exhibiting the same ocular condition confirms Gertsch’s hypothesis and supports the interpretation of the single eye as a stable, species-specific character. Additionally, a new eyeless species from Sucre, Venezuela is described based on both sexes, representing the second eyeless species in the genus. An updated distribution map and an identification key to all species of the genus are also provided.

 Martínez, L. (2026) An eyeless new species of Monoblemma Gertsch, 1941 (Araneae: Tetrablemmidae) from Venezuela, with a new record of the single-eyed Monoblemma unicum Gertsch, 1941 from the Dominican Republic. Zootaxa, 5787 (2), 394–400. https://doi.org/10.11646/zootaxa.5787.2.12