Monoblemma Gertsch, 1941

Monoblemma Gertsch, 1941 View in CoL

Monoblemma Gertsch, 1941: 8 View in CoL ,

type species Monoblemma unica Gertsch, 1941 10, figs. 9–12 (by monotypy).

Diagnosis. Males of the genus Monoblemma can be distinguished from other Neotropical members of Tetrablemmidae by the absence of a conductor or any process emerging from the base of the embolus. In contrast, genera within the tribe Mattini such as Matta , Caraimatta , and Micromatta , which have a well-developed conductor (see Shear 1978: 18, figs. 40–46; Lehtinen 1981: 150, figs. 313–315; Brescovit & Cizauskas 2019: 408, figs. 3E–F, 13A–F). Additionally, Neotropical species of Tetrablemma possess a small, sclerotized process at the base of the embolus, which is also lacking in Monoblemma (see Martínez, Flórez-Daza & Brescovit 2020: 95, 97, 99, figs. 2A– B, 4C–D, 6D–E). Males of Monoblemma are further characterized by a long, filiform embolus and a spermatic duct that runs directly into the embolus without forming loops ( Figs. 3A–D View FIGURE 3 , 5A–D View FIGURE 5 , 7A–D View FIGURE 7 , 12A–D View FIGURE 12 , 16A–D View FIGURE 16 , 20A–C View FIGURE 20 ). The females of the genus are characterized by having very large receptacles with internal rounded glands ( Figs. 3E–F View FIGURE 3 , 7E–F View FIGURE 7 , 20E View FIGURE 20 , 12 View FIGURE 12 E−F, 15E−F, 20F).

Composition. Four species Monoblemma unicum Gertsch, 1941 , Monoblemma cambridgei ( Bryant, 1940) , Monoblemma becki Brignoli, 1978 , and Monoblemma cubaensis sp. nov.

Distribution. From Virgin Islands to Brazil.

Identification key for Monoblemma species

1. Males.............................................................................................. 2

– Females............................................................................................ 5

2. With one single eye or none............................................................................. 3

– With four eyes....................................................................................... 4

3. With a single median eye at the edge of the clypeal declivity ( Fig. 1A–B, D View FIGURE 1 ).......... Monoblemma unicum Gertsch, 1941

– Without eyes............................................................. Monoblemma becki Brignoli, 1978

4. Copulatory bulb longer than wide, with a flat projection at the base of the embolus........ Monoblemma cubaensis sp. nov.

– Copulatory bulb nearly as long as wide, without projection at the base of the embolus................................................................................................... Monoblemma cambridgei ( Bryant, 1940)

5. Central process extremely thin proximally; preanal plate approximately twice as wide as postgenital plate................................................................................... Monoblemma cambridgei ( Bryant, 1940)

– Central process wide along its entire length; preanal plate more than twice as wide as postgenital plate............................................................................................. Monoblemma cubaensis sp. nov.