Matta pititinha sp. n.

Figures 6 ̄9, 30B.

Types. Male holotype from Cave HOL_014 (44°03'54"W, 21°10'58"S) and female paratype from Cave HOL_020 (44°03'59"W, 21°11'06"S), Prados, Minas Gerais, Brazil, 13-16/III/2017, Eq. Spelayon et al. col., deposited in IBSP 196139 and IBSP 196140, respectively.

Other material examined. Brazil. Minas Gerais: Prados, Cave HOL_017 (44°03'55"W, 21°11'04"S), 13-16/ III/2017, Eq. Spelayon et al. col., 1♂ (IBSP 196141; photo) ; Cave HOL_020 (44°03'59"W, 21°11'06"S), 13-16/III/ 2017, Eq. Spelayon et al. col., 1♀ (IBSP 196142; photo) ; Cave HOL_020 (7657089 596891), 19-26/IX/2017, 1♂ 1♀ (IBSP 196145 — SEM ♂ ♀) ; Cave S3_HOL_004 (44°3'55''W 21°11'4''S), 22-30/VII/2014, 1♂ (IBSP 186367) ; Cave S3_HOL_003 (44°3'55''W 21°11'4''S), 22-30/VII/2014, 1♀ (IBSP 186368) ; Cave S3_HOL_002 (44°03'56"W, 21°11'04"S), 22-30/VII/2014, 1♀ (IBSP 186369) ; Cave S3_HOL_021 (44°3'53''W 21°11'1''S), 22- 30/VII/2014, 1♀ (IBSP 186370) ; Cave S2_HOL_008 (44°3'54''W 21°10'58''S), 22-30/VII/2014, 1♀ (IBSP 186371) ; Cave HOL_021 (19-26/IX/2017), 1♂ 1♀ (IBSP 196143) ; Cave HOL_025 (7657253 597004), 19-26/IX/ 2017, 1♀ (IBSP 196144) ; Cave HOL_016 (7657150 597014), 19-26/IX/2017, 1♀ (IBSP 196146) , all collected by Eq. Spelayon; Conceição do Mato Dentro, Cave SERP _0135 (43°23'21''W 19°2'42''S), 04/XII/2013, M.T.M. Souza col., 1♀ (IBSP 186379) ; Morro do Pilar, Cave SERP _0043 (43°15'49''W 19°11'0''S), 31/VIII/2 0 13, 1♀ (IBSP 186380) ; Cave SERP _0050 (43°23'20"W, 19°02'08"S), 2013, 1♀ (IBSP 186381) ; Cave SERP _0013 (43°20'34''W 19°5'55''S), VII/2013, 1♀ (IBSP 186382) , all collected by L.G.S. Soares col.; Santo Antônio do Rio Abaixo, Cave SERP _0032 (43°16'31''W 19°9'58''S), 06/VII/2013, L.G.S. Soares col., 1♂ (IBSP 186378) .

Etymology. The specific name is a noun in apposition that refers to an interjection used by people who live in the Brazilian State of Minas Gerais meaning “very small”, being the smallest described species of this genus.

Diagnosis. Matta pititinha is distinguished from other Matta species by having a combination of males with a retrolateral projection on leg I consisting of four conspicuous setae in large sockets (Fig. 7E ̄F) and an oval dorsal fold of the uterus externus in females (Fig. 6F).

Description. Male (holotype, cave HOL_14, Barroso, Minas Gerais, Brazil). Cephalothorax and abdomen orange. Legs and palps yellow. Total length 0.96. Carapace projected, 0.42 long, 0.37 wide, with rugose surface (Figs 6A, 7A ̄D). Sternal surface reticulate (Fig. 7D). Clypeus long, oblique, four times the diameter of the vestigial eyes (Fig. 7D). Two vestigial frontal eyes (Fig. 7A, D). Cheliceral apophysis short and rounded, with long hairs and translucent median lamina (Fig. 7A ̄D). Leg measurements: I—femur 0.26/ patella 0.11/ tibia 0.24/ metatarsus 0.13/ tarsus 0.22/ total 0.96; II—0.22/ 0.1/ 0.22/ 0.12/ 0.2/ 0.86; III—0.18/ 0.08/ 0.2/ 0.11/ 0.17/ 0.74; IV—0.36/ 0.11/ 0.31/ 0.19/ 0.21/ 1.18. Leg formula 4123. Leg I, spination absent; metatarsus narrowed at base (Fig. 7E). Abdomen ovoid, large sclerotized plate covering dorsal surface (Figs. 6A, 8H); 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 narrow and suboval postgenital plate, rectangular preanal plate, and conical anal plate surrounding spinnerets; laterally with four pairs of narrow plates, most ventral pair very short than others (Fig. 8H), and a line of the four epiandrous spigots.

Male palp: femur with three long setae, with median short and projected salient plates (Fig. 8G); tibia strongly swollen, rounded posteriorly; cymbium small; bulbus pear-shaped, with conductor with elevated border in the retrolateral side, involving the base of the long and sinuous embolus, enlarged at apex, with acute and coiled basally laminar projection (Figs 6B ̄C, 8A–F).

Female (Paratype; HOL_020, Barroso, Minas Gerais, Brazil). Coloration pattern as in male, except legs orange (Fig. 6D). Total length 1.11. Carapace as in male (Fig. 9A ̄B), 0.43 long, 0.37 wide. Clypeus and sternum as in male. Eyes as in male. Chelicerae as in male and with inconspicuous apophysis (Fig. 9A, C). Endites and labium as in male. Leg measurements: I—femur 0.34/ patella 0.12/ tibia 0.26/ metatarsus 0.17/ tarsus 0.21/ total 1.1; II— 0.28/ 0.11/ 0.23/ 0.16/ 0.24/ 1.02; III—0.27/ 0.1/ 0.2/ 0.16/ 0.21/ 0.94; IV—0.38/ 0.11/ 0.33/ 0.21/ 0.28/ 1.31.

Leg formula 4123. Leg spination absent. Pedipalpal tarsus ending in acuminate, smooth pit (Fig. 9D). Abdomen with plates as in males (Fig. 9E). Vulvae externally with ᴗ-shaped receptacle, visible by transparency (Fig. 9F); narrow post genital plate and thin copulatory opening (Fig. 6E). Internally with straight receptaculum and copulatory ducts; central process narrow, with half the length of the receptaculum (Fig. 6F).

Natural history. Matta pititinha sp. n. has morphological characteristics (ocular reduction/vestigial eyes) consistent with isolation to a subterranean environment, and we hypothesize that this species is a troglobite. Specimens were only found in the aphotic regions of caves among mixed lithological formations of iron and carbonate.

Distribution. Known from caves in the State of Minas Gerais, Brazil (Fig. 30B).