Matta humrrum,

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), Zootaxa 4559 (3), pp. 401-444: 427-431

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Matta humrrum

sp. n.

Matta humrrum  sp. n.

Figures 19View FIGURE 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 180287View Materials)GoogleMaps  ; Cave MOC-N3 (44°1'21''W 19°33'1''S), 01-08/VIII/2011, 3♀ ( IBSP 180View Materials 288; SEM)GoogleMaps  ; Cave MOC-30 (44°1'6''W 19°33'2''S), 08-18/II/2011, 1♀ ( IBSP 186419View Materials)GoogleMaps  ; Cave MOC-30 (44°1'6''W 19°33'2''S), 08-18/II/2011, 1♀ ( IBSP 186421View Materials)GoogleMaps  , 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 186376View Materials)  ; Caeté, Cave AP_064 (43°40'10''W 20°0'37''S), 31/V-05/ VI /2012, R. Bessi et al. col., 1♂ ( IBSP 186428View Materials)GoogleMaps  ; Itabirito, Mina do Pico, Cave MP, M.P.A. Oliveira col., 1♀ ( IBSP 182515View Materials)  ; 1♂ 2♀ ( IBSP 182519View Materials; SEM)  ; 1♀ ( IBSP 182523View Materials)  ; 2013, M.P.A. Oliveira col., 1♂ ( IBSP 186396View Materials; photo)  ; Cave MP _008 (20°12'38''S; 43°51'11''W), 20/X/2011, Equipe Carste col., 1♀ ( IBSP 186393View Materials; photo)GoogleMaps  ; Mariana, Cave SPA_03 (20°17'48''S; 45°36'46''W), 12/V/2011, UFLA col., 1♂ ( IBSP 196147View Materials)GoogleMaps  ; Cave SPA_16 (20°17'43''S; 45°37'5''W), 8/V/2011, UFLA col., 1♂ ( IBSP 196148View Materials)GoogleMaps  ; Pedro Leopoldo, Cave HOLC _0025 (19°34'43''S; 44°00'59''W), 22/VII-18/VIII/2015, Equipe Carste col., 1♀ ( IBSP 186506View Materials)GoogleMaps  ; 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 179522View Materials)  ; 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 179523View Materials)  ; Santa Bárbara, Cave APOL _0001 (43°39'56''W 20°0'35''S), 21-25/XI/2011, R. Bessi et al. col., 1♀ ( IBSP 186425View Materials)GoogleMaps  .

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. 20EView FIGURE 20 ̄F), piriform dorsal fold of the uterus externus in females ( Fig. 19FView FIGURE 19) and total absence of eyes ( Fig. 20A, CView FIGURE 20) in both sexes.

Description. Male (holotype, IBSP 186422). Carapace, chelicerae, labium, endites, sternum and abdomen orange. Legs yellowish white ( Fig. 19AView FIGURE 19). Total length 1.48. Carapace projected, 0.64 long, 0.5 wide, with rugose surface ( Fig. 20AView FIGURE 20 ̄C). Sternal surface tenuously reticulate. Clypeus long and oblique ( Fig. 20CView FIGURE 20). Eyes absent ( Fig. 20AView FIGURE 20 ̄C). Cheliceral apophysis short, conic, projected down, with long hairs and translucent median lamina ( Fig. 20BView FIGURE 20 ̄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. 20EView FIGURE 20). Abdomen ovoid, large sclerotized plate covering dorsal surface ( Fig. 20EView FIGURE 20); 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 20GView FIGURE 20 ̄H, 21 ĀB).

Female (IBSP 186422). Coloration pattern as in male ( Fig. 19DView FIGURE 19). Total length 1.49. Carapace as in male, 0.62 long, 0.47 wide. Eyes absent, and clypeus and sternum as in male ( Fig. 21CView FIGURE 21 ̄E). Chelicerae with very small boss, next to border of carapace, with ventral translucent hyaline keel, as in male ( Fig. 21DView FIGURE 21). 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 FView FIGURE 21 ̄G). Vulvae externally with large ᴗ-shaped receptacle ( Fig. 19EView FIGURE 19); narrow post genital plate and wide copulatory opening ( Fig. 21HView FIGURE 21). Internally with sharp receptaculum and large copulatory ducts; central process oval, distally coiled, with half-length of the receptaculum ( Fig. 19FView FIGURE 19).

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. 30BView FIGURE 30).


Mykotektet, National Veterinary Institute


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