Mesabolivar sepitus, Huber, 2018

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 : 117-120

Mesabolivar sepitus sp. n.

Figs 457–458 , 506–515 , 533

Diagnosis. Easily distinguished from most similar known species ( M. beckeri ; see Note below) by modifications of male chelicerae ( Figs 510–511 ; median pair of apophyses much longer); also by male pedipalp ( Figs 506–507, 509 ; shape of procursus: ventral process, distal and prolateral flaps), and by shape of epigynum ( Figs 512–514 ; anterior plate strongly elevated, with pair of indistinct humps and anterior pocket). From all other known congeners also by massive procursus partly wrapped around weakly sclerotized process of genital bulb.

Note. This species is very similar in several respects to a species originally described as Teuia beckeri Huber, 2000 . The proximal palpal segments are almost identical (femur much larger than tibia; tibia distally strongly projecting on retrolateral-ventral side), both species share the unique procursus partly wrapped around the weakly sclerotized process of the genital bulb, and both species share two pairs of processes proximally on the male chelicerae (compare Figs 506–511 and Huber 2000: figs 1259–1262). Teuia beckeri was placed in its own genus because the main putative synapomorphies of Mesabolivar were missing: the median epigynal pocket and the corresponding pair of male cheliceral apophyses close to the median line. The species newly described here clearly shows both of these characters. Molecular data (Eberle et al., unpublished data; see Appendices 1–2) place M. sepitus in the difficilis group of Mesabolivar . As a consequence, the monotypic genus Teuia Huber, 2000 is here synonymized with Mesabolivar González-Sponga, 1998 , and the type species is transferred accordingly: Mesabolivar beckeri (Huber, 2000) , n. comb.

Etymology. The specific name refers to the bulbal process being enveloped or enwrapped by the procursus (Latin sepitus = confined, hedged, surrounded); adjective.

Type material. BRAZIL: Santa Catarina: ♂ holotype, 1♀ paratype, UFMG (21536–37), 4♂ 13♀ paratypes, ZFMK (Ar 19209–10), Serra Geral National Park, Churriado Canyon (29.137°S, 49.953°W), forest near river, 150 m a.s.l., 20.x.2014 (B.A. Huber, L.S. Carvalho).

Other material examined. BRAZIL: Santa Catarina: 3♀ in pure ethanol, ZFMK (Br 14-164), same data as type material . 3♂ 6♀, ZFMK (Ar 19211), Serra Geral National Park, forest along road at ~ 700 m a.s.l. (29.182°S, 50.008°W), 21.x.2014 (B.A. Huber, L.S. Carvalho); 3♀ in pure ethanol, ZFMK (Br 14-169), same data .

Description. Male (holotype)

MEASUREMENTS. Total body length 3.0, carapace width 1.3. Distance PME-PME 120 µm, diameter PME 120 µm, distance PME-ALE 110 µm, distance AME-AME 20 µm, diameter AME 30 µm. Sternum width/length: 0.95/ 0.60. Leg 1: 24.1 (6.1 + 0.5 + 6.4 + 9.6 + 1.5), tibia 2: 3.9, tibia 3: 3.2, tibia 4: 4.8; tibia 1 L/d: 67. Femora 1–4 width (at half length): 0.17, 0.16, 0.35, 0.13. Tibiae 3 also clearly thicker than other tibiae.

COLOR (in ethanol). Carapace ochre-yellow with slightly darker radiating marks, brown around ocular area; sternum light brown; legs ochre-brown, without dark or light rings; abdomen dorsally and laterally densely covered with bluish marks, ventrally with large light brown area in front of gonopore, without darker area in front of spinnerets.

BODY. Habitus as in Fig. 457 ; ocular area raised; carapace with distinct median furrow; clypeus and sternum unmodified.

CHELICERAE. As in Figs 510–511 ; with two pairs of processes proximally: one pair of long pointed apophyses with curved tips near median line and one pair of shorter processes with rounded tips laterally.

PALPS. As in Figs 506–507 ; coxa with large retrolateral apophysis; trochanter barely modified; femur very long, proximally slender with retrolateral process, distally widened; tibia much smaller than femur, distally strongly projecting on retrolateral-ventral side; tarsus with small dorsal process; procursus with large prolateral flap partly wrapped around bulbal process, distally with membranous and sclerotized elements ( Fig. 509 ); genital bulb with simple weakly sclerotized process ( Fig. 508 ).

LEGS. Densely covered with short hairs, without spines and curved hairs, few vertical hairs; retrolateral trichobothrium on tibia 1 at 3.5%; prolateral trichobothrium present on tibia 1; tarsus 1 with ~25 pseudosegments, distally fairly distinct.

Male (variation). Tibia 1 in seven other males 5.7–6.6 (mean 6.2).

Female. In general similar to male ( Fig. 458 ) but all femora (and tibiae) approximately same width. Tibia 1 in 19 females: 4.2–4.7 (mean 4.5). Epigynum as in Figs 512–514 ; anterior epigynal plate simple, protruding, with anterior pocket and pair of indistinct humps; posterior plate with pair of anterior sclerites, lighter median area and posterior wide sclerotized margin. Internal genitalia as in Figs 515 , 533 , with pair of oval pore-plates converging anteriorly.

Natural history. The spiders were found in small cavities in the ground, under dead wood and among the basis of bromeliad leaves. When disturbed, they ran a small distance and vibrated rapidly with small amplitude. Distribution. Known from two neighboring sites in Serra Geral National Park, Santa Catarina state ( Brazil) ( Fig. 739 ).

Figures

FIGURES 447–458. Live specimens, Mesabolivar difficilis group (part 1). 447–448. M. itajai sp. n., male and female from Itajaí.449–451.M.niteroi sp. n., males and female from St.Hilaire/Lange. 452–453. M.saci sp. n., male and female from São Joaquim. 454–456. M. constrictus sp. n., males (regular color and white abdomen morph) and female from Três Barras. 457– 458.M.sepitus sp. n., male and female from Serra Geral.

FIGURES506–511. Mesabolivar sepitus sp. n. (ZFMK Ar 19209). 506–507.Left male palp, prolateral and retrolateral views. 508. Left bulb, retrolateral view. 509. Left procursus, dorsal view. 510–511. Male chelicerae, frontal and lateral views. Scale lines:0.5 (506–509; 508 and509 at same scale), 0.3 (510–511).

FIGURES 512–519. Mesabolivar sepitus sp. n. (512–515, ZFMK Ar 19210) and M. cavicelatus Machado et al., 2007 (516– 519). 512–514. Epigynum, lateral, ventral, and ventral-frontal views (arrow points at pocket). 515. Cleared female genitalia, dorsal view. 516–517. Left procursi, prolateral views, males from Penedo (516, ZFMK Ar 19214) and St. Hilaire/Lange (517, ZFMK Ar 19220). 518–519. Cleared female genitalia, dorsal views, females from Penedo (518, ZFMK Ar 19215) and St. Hilaire/Lange (519, ZFMK Ar 19220). Scale lines:0.3.

FIGURES 520–537. Female epigyna in various views and cleared female genitalia in dorsal views, Mesabolivar difficilis group. 520. M. itajai sp. n. (ZFMK Ar 19197). 521. M. niteroi sp. n. (ZFMK Ar 19198). 522–524. M.difficilis (Mello-Leitão, 1918) (ZFMK Ar 19201), epigyna in lateral, frontal, and posterior (slightly ventral) views. 525–530. M. sp. (“M. difficilis” in Bonaldo et al. 2009) from Presidente Figueiredo (525–527, ZFMK Ar 19205) and from Manaus (528–530, SMNK-ARA 12794) (522–530 at same scale and in same views). 531. M. saci sp. n. (ZFMK Ar 19207). 532. M. constrictus sp. n. (ZFMK Ar 19208). 533. M. sepitus sp. n. (ZFMK Ar 19210). 534–537. M. cavicelatus Machado et al., 2007 (epigyna: ventral views), from Penedo (534–535, ZFMK Ar19215) and from Ubatuba (536–537, ZFMK Ar 19218).

FIGURES 738–739. Known distribution of the Mesabolivar difficilis group.