Matta humhum Brescovit & Cizauskas 2019, sp. n.

Matta humhum sp. n.

Figures 10 ̄14, 30C.

Types. Male holotype and female paratype from Cave AP_066 (43°40'17''W 20°0'32''S), Caeté, Minas Gerais, Brazil, 12-21/XI/2009, R. Bessi et al. col., deposited in IBSP 179486 and IBSP 179487, respectively.

Other material examined. Brazil. Minas Gerais: Caeté, Cave AP_049 (43°41'29''W 20°2'8''S), 12-21/XI/ 2009, R. Bessi et al. col., 1♀ (IBSP 179488); Cave AP_038 (-43.67925100 -20.03098600), epygean, 07-13/VIII/ 2012, R. Andrade & G. P. Perroni et al. col., 1♂ (IBSP 186423); Cave AP_049 (43°41'29''W 20°2'8''S), 31/V-05/ VI /2012, R. Bessi et al. col., 1♂ 1 ♀ (IBSP 186427; photo); Cave AP_066 (43°40'17''W 20°0'32''S), 31/V-05/ VI / 2012, R. Bessi et al. col., 1♂ (IBSP 186429); Barão de Cocais, Cave RF _009 (43°29'13''W 19°55'6''S), 926 m, 10- 21/III/2 0 0 9, 2♀ (IBSP 186411); Cave RF _058 (43°41'8''W 20°1'34''S), 1342 m, 10-21/III/2009, 1♂ (IBSP 186414); Cave RF _005 (43°29'10''W 19°55'3''S), 948 m, 10-21/III/2009, 1♂ (IBSP 186415), all collected by R. Andrade et al.; Cave RF _057 (43°41'8''W 20°1'34''S), 1331 m, 22/VI-03/VII/2009, R. Bessi et al. col., 1♀ (IBSP 186412); Cave RF _069 (43°40'9''W 20°0'35''S), 1502 m, 09-13/XII/2009, R. Bessi et al. col., 1♂ (IBSP 186413); Itabirito, Mina do Pico, 2013, 1♂ 1♀ (IBSP 186394, IBSP 186395, IBSP 186397); Mariana, Cave GER_0052 (20°17'25''S; 43°22'26''W), 15/IX-01/X/2015, 1♀ (IBSP 186517); Cave SM _63 (20°13'51''S; 43°23'44''W), 11-23/ VIII/2014, 1♂ (IBSP 186518); Cave SM _82A (20°13'38''S; 43°27'43''W), 30/IX-04/X/2013, 2♀ (IBSP 186519 – SEM 1 ♀), all collected by Eq. Carste col.; Cave SM, 13/XII/2012, 1♀ (IBSP 189177); Cave FN-012 (43°26'19''W 20°12'29''S), 18/XII/2012, 1♂ (IBSP 189178); Cave FN-010 (43°26'19''W 20°12'27''S), 09/XII/2012, 1♂ (IBSP 189179), Cave FN-012 (43°26'19''W 20°12'29''S), 09/XII/2012, 1♂ 3♀ (IBSP 189180), all collected by BioEspeleo Consultoria Ambiental; Cave FN_12 (20°12'29''S; 43°26'19''W), 16-21/I/2009, 1♂ (IBSP 146209); Cave FN_15 (20°12'20''S; 43°26'9''W), 5-9/V/2009, 1♂ (IBSP 146258); Cave FN_07 (20°12'37''S; 43°26'21''W), 5-9/V/2009, 1♂ (IBSP 146179 — SEM ♂); Cave FN_20, 3-7/II/2011, 1♂ (IBSP), all collected by R. Andrade; Santa Bárbara, Cave APOL _28 (43°40'8''W 20°0'56''S), 30/VI-08/VII/2011, R. Bessi et al. col., 1♀ (IBSP 186424); Cave APOL _28 (43°40'8''W 20°0'56''S), 05-09/XII/2011, R. Bessi et al. col., 1♂ (IBSP 186426).

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 “no”, and in this case indicates that the species is not blind but has vestigial eyes.

Diagnosis. Matta humhum is distinguished from other Matta species by having a combination of males with a leg I with retrolateral projection on a raised base, with four conspicuous setae in elevated sockets in the male (Fig 12A ̄D) and mushroom shape dorsal fold of the uterus externus in females (Fig. 10F).

Description. Male (Holotype, IBSP 179486). Cephalothorax and abdomen orange. Legs and pedipalps yellow (Fig. 10A). Total length 1.07. Carapace projected, 0.47 long, 0.4 wide, with rugose surface (Fig. 11A, C). Sternal surface tenuously reticulate. Clypeus long, oblique, four times the diameter of the vestigial eyes (Fig. 11A). Eye almost vestigial, diameters and interdistances: AME 0.04, AME-AME 0.08 (Figs. 10A, 11A). Cheliceral apophysis short, conical, in the middle area, with long hairs and translucent median lamina (Fig. 11B ̄C). Leg measurements: I—femur 0.36/ patella 0.13/ tibia 0.28/ metatarsus 0.17/ tarsus 0.23/ total 1.17; II—0.32/ 0.13/ 0.24/ 0.16/ 0.18/ 1.03; III—0.26/ 0.12/ 0.2/ 0.16/ 0.2/ 0.94; IV—0.42/ 0.12/ 0.31/ 0.22/ 0.23/ 1.3. Leg formula 4123. Leg I, spination absent; metatarsus narrowed at base (Fig. 12A ̄D). Trichobothria as in M. zuiuda (Fig. 12E). Abdomen ovoid, large sclerotized plate covering dorsal surface (Fig. 11D); ventrally covered by four sclerotized plates (Fig. 11E). Abdominal plates: large pulmonary plate with rounded anterior margin, surrounding pedicel and bearing oval book-lung plates, followed posteriorly by very narrow postgenital plate, suboval preanal plate, and conical anal plate surrounding spinnerets; laterally with four pairs of narrow plates, with same length (Fig. 11D), and a line of the four epiandrous spigots (Fig. 11F). Male palp with femur with three long setae, median short and projected salient plates (Fig. 12F); tibia strongly swollen, rounded posteriorly; cymbium small; bulbus pear-shaped, with conductor with short border, involving the base of the embolus long, curved in the posterior third area and enlarged at apex, with acute and short basal laminar projection (Fig. 13A ̄F).

Female (Paratype, IBSP 179487). Coloration pattern as in male (Fig. 10D). Total length 1.15. Carapace slightly most projected that in male, with long median dorsal setae and fovea with 4-5 small rounded projections (Fig. 14A ̄E); 0.47 long, 0.38 wide. Clypeus and sternum as in male. Eye diameters and interdistances as in male. Chelicerae without apophysis, with ventral translucent hyaline keel as in male (Fig. 14A). Leg measurements: Ifemur 0.36/ patella 0.12/ tibia 0.26/ metatarsus 0.16/ tarsus 0.23/ total 1.13; II—0.32/ 0.11/ 0.23/ 0.15/ 0.22/ 1.03; III—0.23/ 0.11/ 0.19/ 0.16/ 0.2/ 0.89; IV—0.38/ 0.12/ 0.32/ 0.2/ 0.21/ 1.23. Leg formula 4123. Leg spination absent. Pedipalpal tarsus ending in acuminate, smooth pit (Fig. 14F). Abdomen with plates as in male (Fig. 14G). Vulvae externally with ᴗ-shaped receptacle, visible by transparency (Fig. 10E); narrow post genital plate and thin copulatory opening (Fig. 14H). Internally with enlarged receptaculum and narrow at base copulatory ducts; central process narrow, with length of the receptaculum (Fig. 10F).

Natural history. Matta humhum sp. n. is a species known only from caves in the ferruginous formations of the Quadrilátero Ferrífero Iron Region. Specimens were collected in both aphotic and twilight zones and always on the cave floor. Based on reduced eyes and long hairs of trichobothria we hypothesize that this species is a troglobite.

Distribution. Known from caves in Quadrilátero Ferrífero Iron Region in the State of Minas Gerais, Brazil (Fig. 30C).