Mesabolivar jamari,

Huber, Bernhard A., 2018, The South American spider genera Mesabolivar and Carapoia (Araneae, Pholcidae): new species and a framework for redrawing generic limits, Zootaxa 4395 (1), pp. 1-178: 20-23

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Mesabolivar jamari

sp. n.

Mesabolivar jamari  sp. n.

Figs 9–10View FIGURES 1–12, 55–57View FIGURES 55–58, 59–60, 63–65View FIGURES 59–68, 72–74View FIGURES 69–77

Diagnosis. Males are easily distinguished from most known congeners by extremely long distal element of procursus ( Figs 56–57View FIGURES 55–58; similar only in M. tapajos  ); from M. tapajos  by other details of tarsus and procursus (smaller tarsal process, position of dorsal process on procursus; compare Figs 57 and 58View FIGURES 55–58), by armature of male chelicerae ( Figs 59–60View FIGURES 59–68; apophyses stronger), and by shape of epigynum ( Figs 63–64View FIGURES 59–68; larger median depression bordered posteriorly by pocket with distinctive hood; conical lateral processes shorter; epigynum very similar to M. exlineae  , but see Note below).

Note. The epigynum illustrated in Huber (2000) for Mesabolivar exlineae (Mello-Leitão, 1947)  is very similar to the one shown here for M. jamari  (compare Fig. 63View FIGURES 59–68 with Huber 2000: fig. 768). Unfortunately, M. exlineae  is burdened with several problems: (1) the geographic origin is dubious. Mello-Leitão (1947a) gives “Pebas (Perú)” [3.31°S, 71.86°W, 110 m a.s.l.], while the label in the supposed type vial (BMNH 1940.12.30.108) reads “Capachica” [15.64°S, 69.83°W, 3850 m a.s.l.]. Previously, I considered Capachica the type locality and Mello- Leitão’s published locality an error (Huber 2000); however, Capachica is a high altitude place with a relatively dry climate, while all putatively close relatives ( M. pseudoblechroscelis  , M. huambisa  , M. paraensis  , M. maraba  , M. acrensis  ) come from low altitude and high-precipitation areas. (2) The female illustrated in Huber (2000) may not be the holotype. As noted earlier (Huber 2000), Mello-Leitão’s (1947a) illustration of the epigynum looks quite different, even though the text mentions “two horns”. In sum, the supposed type vial in BMNH may be mislabeled, and the true type of M. exlineae  may be lost or misplaced and originate from Pebas indeed.

Etymology. The specific name is derived from the type locality; noun in apposition.

Type material. BRAZIL: Rondônia: ♂ holotype, 1♀ paratype, UFMG (21503–04), 4♂ 5♀ paratypes, ZFMK (Ar 18954), Floresta Nacional do Jamari, ‘sites 2 & 3’ (9.22°S, 62.93°W – 9.26°S, 62.92°W), 110 m a.s.l., 24.x.2016 (B.A. Huber, L.S. Carvalho).

Other material examined. BRAZIL: Rondônia: 1♀ in pure ethanol, ZFMK (Br 16-301), same data as types  ; 1♀ (apparently teratological, see below; assigned tentatively), ZFMK (Ar 18955), same data as types  . 1♀, ZFMK (Ar 18956), Floresta Nacional do Jamari, Gran Piedra (9.198°S, 63.082°W), 160 m a.s.l., 25.x.2016 (B.A. Huber, L.S. Carvalho).GoogleMaps 

Description. Male (holotype)

MEASUREMENTS. Total body length 2.7, carapace width 1.25. Distance PME-PME 110 µm, diameter PME 130 µm, distance PME-ALE 100 µm, distance AME-AME 30 µm, diameter AME 40 µm. Sternum width/length: 0.95/ 0.60. Leg 1: 39.5 (9.7 + 0.5 + 9.6 + 17.5 + 2.2), tibia 2: 6.4, tibia 3: 4.4, tibia 4: 6.8; tibia 1 L/d: 83. Femora 1–4 width (at half length): 0.17, 0.19, 0.20, 0.18.

COLOR (in ethanol). Carapace ochre-orange, with black median line and pair of whitish areas beside ocular area; ocular area and clypeus not darkened; sternum medially slightly darker (orange to light brown); legs ochre to light brown, with darker rings on femora (subdistally) and tibiae (proximally and subdistally), tips of femora and tibiae whitish; abdomen greenish-gray, with dark internal marks dorsally and laterally, no ventral marks.

BODY. Habitus as in Fig. 9View FIGURES 1–12; ocular area raised (higher than usual in the genus); carapace with distinct median furrow; clypeus slightly swollen and whitish, with sclerotized margin; sternum unmodified.

CHELICERAE. With pair of long cylindrical apophyses with strongly sclerotized hooked tips ( Figs 59–60View FIGURES 59–68).

PALPS. As in Figs 55–56View FIGURES 55–58; coxa with conical retrolateral apophysis; trochanter with finger-shaped retrolateral apophysis; femur very large, proximally with retrolateral apophysis and prolateral hump set with short hairs; tarsus with large rounded dorsal process, with one strong and two regular hairs bent towards dorsal; procursus with widened median section, dorsal process, and long distal process apparently provided with gland and duct ( Fig. 57View FIGURES 55–58); bulb with distally bifid process.

LEGS. Without spines and curved hairs, few vertical hairs; retrolateral trichobothrium on tibia 1 at 2.5%; prolateral trichobothrium present on tibia 1; tarsus 1 with ~30 pseudosegments, distally fairly distinct.

Male (variation). Tibia 1 in four other males: 9.5, 9.6, 9.8, 10.7. Two males asymmetric with respect to trichobothria on palpal tibiae: one male with both trichobothria very proximally on one side; other male without proximal trichobothrium on one side.

Female. In general similar to male ( Fig. 10View FIGURES 1–12) but carapace ochre-brown rather than orange, with large brown median mark. Tibia 1 in seven females: 5.5–6.0 (mean 5.8). Epigynum as in Figs 63–64View FIGURES 59–68, 72–73View FIGURES 69–77; anterior plate with large median depression bordered posteriorly by large pocket; pair of conical lateral processes directed obliquely towards posterior; posterior plate large, simple. Internal genitalia as in Figs 65View FIGURES 59–68, 74View FIGURES 69–77, with roughly triangular poreplates and distinctive median structure (arrow in Fig. 65View FIGURES 59–68; curved median tube, possibly to accommodate long processes of procursi). One female from type locality with much lower epigynal processes, apparently teratological; tibia 1 in this female: 5.4.

Natural history. The spiders were found very close to the ground, in webs that were mostly hidden in the leaf litter, under logs, or in small cavities in the ground. A small part of the domed sheet was visible from outside, and the spiders were resting in the back.

Distribution. Known from type locality in Rondônia state ( Brazil) only ( Fig. 722View FIGURES 722–723).


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