Matta humrrum Brescovit & Cizauskas 2019, sp. n.
Creators: name: Brescovit, Antonio D.
name: Cizauskas, Igor
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Tetrablemmidae
Matta
Matta humrrum

description: Matta humrrum sp. n.
Figures 19 ̄21, 30B.
Types. Male holotype and female paratype from Cave MOC-N3 (44°01'21''W 19°33'01''S), Matozinhos, Minas Gerais, Brazil, 04-15/IV/2011, F.P. Franco & C.A.R. Souza et al. col., deposited in IBSP 186422.
Other material examined. Brazil. Minas Gerais: Matozinhos, Cave MOC-117 (44°1'7''W 19°33'0''S), 01-08/ VIII/2011, 1♀ (IBSP 180287); Cave MOC-N3 (44°1'21''W 19°33'1''S), 01-08/VIII/2011, 3♀ (IBSP 180 288; SEM); Cave MOC-30 (44°1'6''W 19°33'2''S), 08-18/II/2011, 1♀ (IBSP 186419); Cave MOC-30 (44°1'6''W 19°33'2''S), 08-18/II/2011, 1♀ (IBSP 186421), all collected by F. P. Franco & C. A. R. Souza et al. col.; Barão de Cocais, Cave BRU_034, X/2013, Ativo Ambiental col., 2♀ 1 imm. (IBSP 186376); Caeté, Cave AP_064 (43°40'10''W 20°0'37''S), 31/V-05/ VI /2012, R. Bessi et al. col., 1♂ (IBSP 186428); Itabirito, Mina do Pico, Cave MP, M.P.A. Oliveira col., 1♀ (IBSP 182515); 1♂ 2♀ (IBSP 182519; SEM); 1♀ (IBSP 182523); 2013, M.P.A. Oliveira col., 1♂ (IBSP 186396; photo); Cave MP _008 (20°12'38''S; 43°51'11''W), 20/X/2011, Equipe Carste col., 1♀ (IBSP 186393; photo); Mariana, Cave SPA_03 (20°17'48''S; 45°36'46''W), 12/V/2011, UFLA col., 1♂ (IBSP 196147); Cave SPA_16 (20°17'43''S; 45°37'5''W), 8/V/2011, UFLA col., 1♂ (IBSP 196148); Pedro Leopoldo, Cave HOLC _0025 (19°34'43''S; 44°00'59''W), 22/VII-18/VIII/2015, Equipe Carste col., 1♀ (IBSP 186506); Rio Acima, Cave VG-26 (43°53'55''W 20°6'60''S), 29/III-01/IV/2011, R. Andrade & I. Cizauskas et al. col., 1♀ (IBSP 179522); Cave VG-26 (43°53'55''W 20°6'60''S), 29/III-01/IV/2011, R. Andrade & I. Cizauskas et al. col., 1♀ (IBSP 179523); Santa Bárbara, Cave APOL _0001 (43°39'56''W 20°0'35''S), 21-25/XI/2011, R. Bessi et al. col., 1♀ (IBSP 186425).
Etymology. The specific name is a noun in apposition that refers to an expression used by people in the Brazilian State of Minas Gerais meaning “yes”, and in this case indicates that this species is blind.
Diagnosis. Matta humrrum is distinguished from other Matta species by having a combination of leg I of male with retrolateral projection on a pedunculated base, with four conspicuous setae in sturdy sockets (Fig. 20E ̄F), piriform dorsal fold of the uterus externus in females (Fig. 19F) and total absence of eyes (Fig. 20A, C) in both sexes.
Description. Male (holotype, IBSP 186422). Carapace, chelicerae, labium, endites, sternum and abdomen orange. Legs yellowish white (Fig. 19A). Total length 1.48. Carapace projected, 0.64 long, 0.5 wide, with rugose surface (Fig. 20A ̄C). Sternal surface tenuously reticulate. Clypeus long and oblique (Fig. 20C). Eyes absent (Fig. 20A ̄C). Cheliceral apophysis short, conic, projected down, with long hairs and translucent median lamina (Fig. 20B ̄D, G). Leg measurements: I—femur 0.58/ patella 0.18/ tibia 0.42/ metatarsus 0.28/ tarsus 0.33/ total 1.79; II—0.52/ 0.16/ 0.4/ 0.27/ 0.28/ 1.63; III—0.44/ 0.15/ 0.34/ 0.23/ 0.28/ 1.44; IV—0.55/ 0.16/ 0.53/ 0.37/ 0.32/ 1.93. Leg formula 4123. Leg spination absent; metatarsus narrowed at base (Fig. 20E). Abdomen ovoid, large sclerotized plate covering dorsal surface (Fig. 20E); ventrally covered by four sclerotized plates. Abdominal plates: large pulmonary plate with rounded anterior margin, surrounding pedicel and bearing oval book-lung plates, followed posteriorly by very narrow postgenital plate, rectangular preanal plate, and conical anal plate surrounding spinnerets, laterally with four pairs of narrow plates, with same length, and a line of the four epiandrous spigots. Male palp: femur with three long setae, median short and small number of projected plates; tibia strongly swollen, rounded posteriorly; cymbium small; bulbus pear-shaped, with conductor with elevated and sinuous border, involving the base of the embolus long, sinuous, and enlarged at apex, with acute and relatively short basal laminar projection, with enlarged base (Figs 20G ̄H, 21 ĀB).
Female (IBSP 186422). Coloration pattern as in male (Fig. 19D). Total length 1.49. Carapace as in male, 0.62 long, 0.47 wide. Eyes absent, and clypeus and sternum as in male (Fig. 21C ̄E). Chelicerae with very small boss, next to border of carapace, with ventral translucent hyaline keel, as in male (Fig. 21D). Leg measurements: Ifemur 0.52/ patella 0.16/ tibia 0.41/ metatarsus 0.29/ tarsus 0.31/ total 1.69; II—0.45/ 0.14/ 0.37/ 0.26/ 0.31/ 1.53; III—0.42/ 0.15/ 0.33/ 0.24/ 0.26/ 1.4; IV—0.57/ 0.15/ 0.53/ 0.36/ 0.32/ 1.93. Leg formula 4123. Leg spination absent. Pedipalpal tarsus ending in acuminate, smooth pit. Abdomen with plates as in male (Fig. 21 F ̄G). Vulvae externally with large ᴗ-shaped receptacle (Fig. 19E); narrow post genital plate and wide copulatory opening (Fig. 21H). Internally with sharp receptaculum and large copulatory ducts; central process oval, distally coiled, with half-length of the receptaculum (Fig. 19F).
Natural history. Matta humrrum sp. n. is the only species described in this paper that completely lacks eyes. Specimens were collected mainly in iron caves in the Quadrilátero Ferrífero Iron Region. Individuals were found in deep regions of the caves under stones on the cave floor. We hypothesize that this species is a troglobite.
Distribution. Known only from caves in the State of Minas Gerais, Brazil (Fig. 30B).
description: Published as part of Brescovit, Antonio D. & Cizauskas, Igor, 2019, Seven new species of the spider genus Matta Crosby from caves in the State of Minas Gerais, Brazil (Araneae, Tetrablemmidae), pp. 401-444 in Zootaxa 4559 (3) on pages 427-431, DOI: 10.11646/zootaxa.4559.3.1, http://zenodo.org/record/2627047