Microstigmatidae Roewer, 1942

Dupérré, Nadine & Tapia, Elicio, 2025, Revision of the Ecuadorian Microstigmatidae (Araneae: Mygalomorphae), with the description of six new species, European Journal of Taxonomy 1007, pp. 87-132 : 89-90

Family Microstigmatidae Roewer, 1942

Type genus

Microstigmata Strand, 1932 by original designation.

Composition

Angka Raven & Schwendinger, 1995 , Envia Ott & Höfer, 2004 , Ixamatus Simon, 1887 , Kiama Main & Mascord, 1969 , Micromygale Platnick & Forster, 1982 , Microstigmata Strand, 1932 , Ministigmata Raven & Platnick, 1981 , Pseudonemesia Caporiacco, 1955 , Spelocteniza Gertsch, 1982 , Tonton Passanha, Cizauskas & Brescovit, 2019 , Xamiatus Raven, 1981 .

Diagnosis

Distinguished from other genera of Nemesoidina (sensu Montes de Oca et al. 2022) by the following combination of characters: tarsi not flexible ( Figs 2D , 22C ); inferior tarsal claw present; intercheliceral tumescence inconspicuous ( Fig. 7C ); pustulose or scaly cuticule present ( Fig. 25C–D ). Furthermore members of the subfamily Microstigmatinae can be further delineated as follows: tribe Microstigmatini are distinguished by their superior tarsal claw biseriate; pustulose leg cuticle ( Fig. 25C–D ); highly elevated, smooth tarsal organ (visible under SEM) ( Figs 25A , 28F , 29E ) and smooth trichobothrial base ( Fig. 28C ); cymbium without spines ( Figs 8A , 17A ); those of the tribe Pseudonemesiini are distinguished by their superior tarsal claw biseriate; scaly cuticle on leg ( Indicatti & Villarreal 2016: fig. 3c); low tarsal organ with concentric rings, not observed for Envia ( Indicatti & Villarreal 2016: fig. 5a); corrugated trichobothrial base ( Indicatti & Villarreal 2016: fig. 5c–d); cymbium with spines ( Fig. 3A ).

Members of the subfamily Micromygalinae are diagnosed by the combination of the following characters: superior tarsal claw uniserate; low tarsal organ with concentric rings ( Platnick & Forster 1982: fig. 7; Passanha et al. 2019: fig. 1e); scaly cuticule ( Platnick & Forster 1982: fig. 8); trichobothria absent on tarsi but present on metatarsi (in Micromygale, Platnick & Forster 1982 : fig. 9) and present with corrugated bases on tarsi (in Tonton, Passanha et al. 2019 : fig. 1c).

Description

Tiny to medium-sized mygalomorph spiders (0.75–31.00); 0, 2, or 8 eyes in quadrangle; cephalothorax elongated, oval, fovea variable; anterior lobe of maxillae not well-developed; spinnerets short (only two in Ministigmata , with two vestigial in Pseudonemesia ); legs with pustulose or scaly cuticle; leg tarsi with three claws; tarsi and / or metatarsi with filiform trichobothria; tarsal organ elevated and smooth or low with concentric ridges.

Distribution

Australia, Central and South America, South Africa and Thailand.

Figures

Fig. 2. Pseudonemesia scutata sp. nov., ♂, holotype (ECFN 6985; QCAZ). A. Carapace, dorsal view. B. Sternum, ventral view. C. Abdomen, dorsal view (arrow points to scutum). D. Leg I, prolateral view (arrow points to rounded spine). Scale bars: 0.5 mm.

Fig. 22. Pastaza vegai gen. et sp. nov., ♂, holotype (ECFN 11675; QCAZ). A. Carapace, dorsal view. B. Sternum, ventral view. C. Tibia I, retrolateral view. Scale bars: 1.0 mm.

Fig. 7. Spelocteniza pampenita sp. nov., ♂, holotype (ECFN 11665; QCAZ). A. Carapace, dorsal view. B. Sternum, ventral view. C. Chelicerae (arrow points to intercheliceral tumescence). D. Leg I, retrolateral view. Scale bars: A–B = 1.0 mm; C–D = 0.5 mm.

Fig. 25. Spelocteniza ashmolei Gertsch, 1982, ♀, holotype (AMNH_IZC 00357161), SEM. A. Palp tarsus, dorsal view (arrow points to tarsal organ). B. Tarsus III, dorsal view (arrow points to tarsal organ). C. Tarsus IV trichobothria, dorsal view. D. Tarsus II cuticle, dorsal view.

Fig. 28. Spelocteniza pampenita sp. nov., ♂, paratype (ZMH-A0030710; ZMH). SEM. A. Palpal bulb, ventral view. B. Palp, retrolateral view. C. Trichobothria, tarsus I. D. Tarsus III, dorsal view (arrow points to tarsal organ). E. Tarsus I, dorsal view. F. Tarsus I, tarsal organ.

Fig. 29. SEM. A. Spelocteniza pampenita sp. nov., ♂, paratype (ZMH-A0030710; ZMH), tarsus II, dorsal view (arrow points to tarsal organ). B–D. Pastaza aureliae gen. et sp. nov., ECFN 7948 (QCAZ) B. Tarsus III, dorsal view. C. Tarsus III, dorsal view (arrow points to tarsal organ). D. Tarsal organ II, dorsal view. E. Pastaza roberti gen. et sp. nov. (ZMH-A0030714), tarsus I, dorsal view. F. Pastaza vegai gen. et sp. nov., (QCAZ), tarsus I, dorsal view (arrow points to tarsal organ).

Fig. 8. Spelocteniza pampenita sp. nov., ♂, holotype (ECFN 11665; QCAZ). A. Palp, prolateral view. B. Palp, retrolateral view. C. Bulb, prolateral view (arrow points to tegular heel). D. Bulb, ventral view. E. Bulb, retrolateral view. Abbreviations: see Material and methods. Scale bars: A–B = 0.5 mm; C–E = 0.1 mm.

Fig. 17. Pastaza roberti gen. et sp. nov., ♂, holotype (ECFN 11674; QCAZ). A. Palp, prolateral view. B. Palp, retrolateral view. C. Bulb, prolateral view (arrow points to tegular heel). D. Bulb, ventral view (arrows point to keels). E. Bulb, retrolateral view. Scale bars: 0.5 mm.

Fig. 3. Pseudonemesia scutata sp. nov., ♂, holotype (ECFN 6985; QCAZ). A. Palp, prolateral view. B. Palp, retrolateral view. C. Bulb, prolateral view. D. Bulb, ventral view E. Bulb, retrolateral view. Scale bars: A–B = 0.5 mm; C–E = 0.1 mm.