Brasilomma Brescovit, Ferreira & Rheims
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publication ID |
https://doi.org/ 10.5281/zenodo.209007 |
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publication LSID |
lsid:zoobank.org:pub:E2DEE417-A78A-48B6-9412-FF1DC6B5C3FD |
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DOI |
https://doi.org/10.5281/zenodo.6179654 |
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persistent identifier |
https://treatment.plazi.org/id/D95187DC-C27C-FF9F-FF6D-947975B3FE43 |
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treatment provided by |
Plazi |
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scientific name |
Brasilomma Brescovit, Ferreira & Rheims |
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Genus Brasilomma Brescovit, Ferreira & Rheims View in CoL gen. nov.
Etymology. The generic name is a contraction of Brazilian Lygromma , neuter in gender.
Type species: Brasilomma enigmatica sp. nov.
Diagnosis. Within Theuminae, Brasilomma gen. nov. is distinguished from other genera by the absence of clavate translucent setae on the abdominal dorsum (see Platnick et al. 2005: fig. 31). It further differs from Chileuma by the absence of eyes (species of Chileuma have six well developed eyes); from Chilongius by lacking their centrally situated epigynal atrium (see Platnick et al. 2005: figs 65, 69); from Tricongius by lacking the protruding chelicerae with relatively long fangs and modified cheliceral promargin (see Platnick & Höfer, 1990: 5) and from Lygromma by having a single long prong in the RTA, instead of two or more short ones (see Platnick & Shadab, 1976: figs 10, 14). It can be distinguished from the remaining South American prodidomids by the male palps with a large triangular projection, covering the base of the embolus ( Fig. 18 View FIGURES 18 – 22 ) and by the distal border of the tegulum projected over the base of the conductor and median apophysis ( Figs 18–19 View FIGURES 18 – 22 ).
The females are distinguished by the blind, posterior atrium ( Fig. 20 View FIGURES 18 – 22 ) in the epigynum and by the anteriorly widened copulation ducts ( Fig. 21 View FIGURES 18 – 22 ) arising from an internal, mushroom-shaped plate ( Fig. 22 View FIGURES 18 – 22 ).
Description. Small spiders, total length 2.3–3.0. Prosoma ovate, narrowed anteriorly to slightly less than half its maximum width; surface covered with short, light, needle-like setae; thoracic groove short, longitudinal, on posterior third of prosoma. Eyes absent, with only a pair of vestigial whitish spots anteriorly ( Figs 1–2 View FIGURE 1 View FIGURE 2 ). Chelicerae vertical, not divergent; promargin not modified, with three pro and one retromarginal teeth in males; seven pro and five retromarginal denticles in females; fang longer than chelicerae width; chilum entire. Labium pentagonal, slightly wider than long, widest posteriorly. Endites rectangular, convergent anteriorly; serrula short and slightly curved. Sternum longer than wide, projected between coxae IV; surface smooth, with long, darkish setae along lateral margins. Legs covered with short, light, needle-like setae; leg formula 4123; trochanter smooth, without deep notch; metatarsi and tarsi without scopula; tarsi with two pectinate claws, I–II long toothed ( Fig. 6 View FIGURES 3 – 8 ) and III–IV short toothed ( Fig. 8 View FIGURES 3 – 8 ); specialized claw teeth and specialized setae at base of claws ( Figs 6–8 View FIGURES 3 – 8 ); claw tufts composed of 4–5 widened spatulate setae ( Figs 6–8 View FIGURES 3 – 8 ); trichobothria with deep ridges, 4–5 dorsal on metatarsi and 2–3 dorsoprolateral on all tarsi ( Fig. 1–2 View FIGURE 1 View FIGURE 2 ). Tarsal organ with elevated and rounded border ( Fig. 5 View FIGURES 3 – 8 ). Opisthosoma oval, longer than wide, covered with short, light, needle-like setae and anteriorly with long, dark, posteriorly curved setae; colulus absent. Six spinnerets, anterior laterals elongated, not advanced anteriorly, widely separated ( Figs 13–15 View FIGURES 13 – 17 ), bearing long major ampullate gland spigots, few piriform gland spigots and many accompanying setae ( Figs 9–10 View FIGURES 9 – 12 , 13–14 View FIGURES 13 – 17 ); posterior medians small, narrow, contiguous ( Figs 14–15 View FIGURES 13 – 17 ); posterior laterals almost contiguous, with at least 3 aciniform gland spigots with narrow shaft, and at least two spigots with larger shafts, probably of cylindrical glands ( Figs 11–15 View FIGURES 9 – 12 View FIGURES 13 – 17 ). Male palp: tibia short, approximately half cymbium length, with single conical RTA, two strong, elongate setae prolaterally and one dorsally; cymbium ovate, without scopula and with two or three strong, dark setae; tegulum ovoid with distal triangular projection partially covering the embolus; embolus short and conical, arising prolaterally and gently curving retrolaterally towards laminar, hyaline conductor; median apophysis present, hook-shaped, slightly wider at base ( Figs 18–19 View FIGURES 18 – 22 ). Epigynum wider than long with posterior, blind rounded depression ( Fig. 20 View FIGURES 18 – 22 ); pair of copulation openings on internal mushroom-shaped, sclerotized plate ( Fig. 21 View FIGURES 18 – 22 ); copulation ducts proximally wide and straight, distally narrowed and very convoluted; spermathecae indistinct; fertilization ducts short, hook-shaped and pointing away from each other ( Fig. 22 View FIGURES 18 – 22 ).
Distribution. Known from three caves in the state of Minas Gerais, Brazil.
Composition. Monotipic.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.