Bunostigma singulare Mello-Leitão, 1935

Kury, Adriano Brilhante & Caramori, Laura Regina, 2021, An unusual cryptogeobiid from southeastern Brazil revisited (Opiliones, Laniatores, Gonyleptoidea), Papéis Avulsos de Zoologia 61, pp. 1-7 : 4-7

Bunostigma singulare Mello-Leitão, 1935 ( Figs. 1-5 )

Bunostigma singularis Mello-Leitão, 1935a: 10 , fig. 2.

‡ Incorrect originally applied gender declination.

Species epithet is a Latin two-termination adjective of the third-declension (singularis, singularis, singulare). Bunostigma singularis – Soares, 1945: 370; Soares &

Soares, 1954: 240; Kury, 2003: 201. Bunostigma singulare: Kury & Alonso-Zarazaga, 2011: 58 . Bunostigma singulare – Kury, 2014: 8, fig. 28N.

Type data: ♂ lectotype, 1♂ 3♀ paralectotypes ( MNRJ 41788) and 2♀ paralectotypes ( MNRJ 42677), RJ, Rio de Janeiro, Parque Nacional da Tijuca, Bico do

Papagaio peak, R. Arlé leg. Other material examined: 1♂ ( MNRJ 4765) RJ, Rio de Janeiro, Parque Nacional da Tijuca, 03.iii.2001, A.P.L. Giupponi, D. R. Pedroso & D.F. Almeida leg./ 1♂ 1♀ ( MNRJ 4950), same loc., Trilha da Caveira 08.ix.2001, A. Pérez & A.P.L. Giupponi leg./ 1♂ 1♀ ( MNRJ 7679), same loc., close to Gruta do Belmiro, 15.vi.2012, A.B. Kury, C.M. Barros, D. R. Pedroso & G.S. Miranda leg./ 1♂ ( MNRJ 59054) Brasil, RJ, Nova IguaÇu, REBIO do Tinguá, surroundings of the seat (-22.58199°, -43.43641°, alt.: 150 m) 07.i.2020, A.B. Kury, M.A. Medrano & D. R. Pedroso leg.

Redescription, male (MNRJ 7679). Measurements: CL = 0.83, CW = 1.20, AL = 1.34, AW = 1.69. Tr I = 0.19, Fe I = 0.89, Pa I = 0.45, Ti I = 0.60, Mt I = 0.75, Ta I = 0.69; Tr II = 0.26, Fe II = 1.25, Pa II = 0.57,Ti II = 0.88, Mt II = 0.99, Ta II = 0.88;Tr III = 0.23,Fe III = 1.16,Pa III = 0.48,Ti III = 0.83, Mt III = 1.05, Ta III = 0.77; Tr IV = 0.32, Fe IV = 1.08, Pa IV = 0.58, Ti IV = 0.95, Mt IV = 1.31, Ta IV = 0.72.

Dorsum ( Figs. 1C , E-F, 2A-C): Dorsal scutum roughly theta type (bell-shaped):with laterals of carapace strongly widening posteriorly; mid-bulge noticeably short and only a little wider than the rest; abdominal scutum wider than carapace with sides almost parallel. Carapace with shallow C-shaped groove, entirely smooth; lateral ridges faintly marked; preocular mound very low, smooth. Ocularium low, elliptical (in dorsal view), with broad middle hump (in frontal view, Fig. 2C ), situated in the middle of the carapace, entirely unarmed. Body outline in lateral view convex, continuous, without steep risings or pits. Lateral margins of scutum entirely smooth. Mesotergum divided into 4 areas. Area I with anterior and posterior margins straight and expanded on the laterals. Area II with anterior margin slightly arched frontwards and posterior margin straight. Area III with anteri- or margin straight, posterior arched backwards. Area IV with anterior margin arched backwards,following area III and posterior margin also arched backwards, with small V-shaped cleft. All areas and free tergites entirely smooth and unarmed. Posterior border of dorsal scutum gently convex, with laterals merging into articular membrane along with free tergite I ( Figs. 2 A-B).

Venter ( Figs. 1D , 2B , D-F): Coxae I-IV and stigmatic area only finely granular, with transverse rows of setiferous tubercles stouter anteriorly. Free sternites each with row of minute setiferous tubercles. Cx I to III transversal to main body axis; Cx II curved around Cx I, as long as Cx I, much longer than Cx III. Cx II and III delimit a narrow sternum. Maxillary lobe of Cx II as a small triangle. Cx I movable. Cx II linked to Cx III by four pairs of lateral tubercular bridges; Cx III linked to Cx IV by six to seven pairs of large lateral tubercular bridges. Cx IV oblique, as large as all others combined.Stigmatic area roughly triangular, only separated from Cx IV by a difference in height, fused to sternite II, with forked frames around the stigmata ( Fig. 2D ). Sternite II strongly thickened. Stigmata small, entirely longitudinal and framed by a complex formed by a forked structure + the retroapical apophysis of Cx IV ( Fig. 2F ). Cx IV with a well-developed wrench-shaped retroapical apophysis flanking the stigma and deeply embedded on the sternite II. Ventral complex without any lobes, expansions, fasciolate hyaline apophyses or cluster of modified setae.

Mouthparts ( Figs. 3 A-C): Basichelicerite with well-developed bulla, separated from peduncle by a narrow waist. Its mesal surface covered with patches of small denticles, but without any plectra. Cheliceral hand weak, monomorphic. Pp Tr with 1 large ventral megaspine, Fe with 2 small megaspines, Pa short, with one meso-distal setiferous tubercle, all of those with slender setae. Pedipalps stunt; Pp Fe cylindrical, only gently convex dorsally and moderately compressed, without stridulatory grid and with stout meso-distal setiferous tubercle. Spination of Pp cage: Ti mesal IiIi, ectal IÎI, Ta mesal IIi, ectal iIi.

Legs ( Figs. 1 A-G, 4A-H): Legs I to III with all articles without head (but with tapering apex), slightly sinuous. smooth, unarmed and without special modifications. Skirt ungrooved, semicircular, without an axis, radiating Fe I-II substraight, III-IV strongly arched. Mt I-IV not in dorsal view around a hollow center, with gently serrate spindled, divided into a short distal calcaneus (shortest margins.

in Mt IV) and a proximal astragalus. Cx IV: rather weak,

expanding only slight laterally and posteriorly reaching Color (in alcohol): Dorsal and ventral body background mid area II, armed with a distal prodorsal conical apophy- vivid orange (centroid 48). Mesotergum with three longisis.Tr IV:subsquare, with a large blunt median retroapical tudinal deep brown (centroid 56) stripes; with coalesce apophysis. Fe IV: cylindrical, arched, bearing a proventral on areas III-IV.This darker shade also occurs on the lateral row of setiferous tubercles on the distal half, growing of scutum, middle of area V and lateral of free tergites stouter apically. Ti IV: uniformly incrassate, with one api- and only very sparsely on the ventral surface.Color backcal proventral spur and a row of six retrolateral spines ground of chelicerae, pedipalps and legs I to IV all light ( Fig. 1B ). Tarsal counts (Figs. E-H): 4(3)/5(3)/5/5. greenish yellow (centroid 101), densely reticulated and honeycombed with deep brown except on: trochanters Male genitalia ( Figs. 5 A-G): Distal part of truncus I-IV, a few broad rings on femora I-IV and the most of slightly bent as an oblique malleus and an erect large pedipalps.

lamina parva (LP). Dorsal malleus without hyaline but-

ton but with a long deep slit. Glans sac rigid, unfolded, Sexual dimorphism: Male (MNRJ 7679) contrasted with gutter-shaped. Lamina parva prismatic, subrectangu- female (MNRJ 7679). Female ( Fig. 1G ) in general color lar (in ventral view) with rounded corners. Nine pairs of and proportions of body/appendages (except leg IV) macrosetae (MS) A to E arranged as follows: MS A1 stout, very similar to male. Abdominal part of dorsal scutum inserted on dorso-apical surface of malleus, close to the is flaring (as opposed to parallel in males). Coxa without base of LP.MS A2 stout, inserted on lateral surface of mal- distal prodorsal and retroapical apophyses; trochanter leus, more proximal than A1. MS B1 as strong as A1-A2, and tibia IV unarmed.

located in the ventrally on malleus. MS C1-C3 short,

smooth, inserted close to each other, located on the ven-

tro-latero-distal edge of LP. MS D1 very short, located DISCUSSION of the lateral surface of LP, close to C3. MS E2 similar in size to MS C, E1-2 forming a quadrangle on ventro-dis- Kury (2014: 14, fig. 7) recognized two main clades tal surface of LP, E2 much larger than E1. Stylus with a in Cryptogeobiidae , which he called A and B. The few distal folds, without dorsal accessory plate (DAPG), clade A contains several species with swollen or clavate podomeres in leg IV, while clade B contains the species mostly with a huge, hooked spine on the ocularium and a mitobatine-like sexual dimorphism on leg IV, where the podomeres in males, especially the femur IV, are straight and much elongate. Bunostigma belongs to the clade A, along with five other genera ( Cryptogeobius Mello-Leitão, 1935 , Heteromeloleptes Mello-Leitão, 1931 , Paratricommatus Piza-Jr., 1943, Pseudophalangodes Roewer, 1912 and Zalanodius Mello-Leitão, 1936 ), and some undescribed terminals. Although Bunostigma was resolved as sister-group to Cryptogeobius , there is a wide morphological gap between both genera, mostly because of the unique scutum outline in Bunostigma and the strong armature of Cx and Tr IV in Cryptogeobius . Although monotypic genera are a noxious heirloom of the Roewerian System, this gap makes it more intuitive to leave Bunostigma singulare to stand alone in its own genus.

There are stumbling blocks hampering the attainment of a more refined phylogeny hypothesis for the Cryptogeobiidae : (1) most species are poorly known, and (2) there is a great number of undescribed species. Therefore, refining the morphological description of the type species of a genus is an important step towards this goal.

Figures

Figure 3. Bunostigma singulare Mello-Leitão, 1935, male (MNRJ 7679), mouth parts. (A) Right chelicera, mesal view. (B) Same, detail of cuticular sculpture of basichelicerite.(C) Right pedipalpus,mesal view.Scale bars:A,C = 100 μm; B = 20 μm.

Figure 5. Bunostigma singulare Mello-Leitão, 1935, male (MNRJ 7679), genitalia, penis, pars distalis. (A) Dorsal view. (B) Dextrolateral view. (C) Ventral view. (D) Same,magnified.(E)Apical view.(F)Glans,dorsolateral view.(G) Same,dorsal view.Scale bars:A = 50μm;B-C= 20μm;D-G =10 μm.Colorof macrosetae are: MS A (light blue),MS B (dark blue),MS C (magenta),MS D (orange) and MS E (green).

Figure1.HabitusofBunostigmasingulareMello-Leitão,1935.(A)Male,invivo atTinguá,RJ.(B)Same,anotherview.(C)Male(MNRJ7679)habitusdorsalview.(D)Same, ventral view.(E) Same,panoramicview.(F)Same,dextrolateral view.(G)Female (MNRJ7679)habitusdorsalview.Scalebars:A-G =1 mm.All photographsby A.B.Kury.

Figure2.BunostigmasingulareMello-Leitão,1935,male(MNRJ7679).(A)BodyandproximallegIV,dorsalview.(B)BodyandCxIV,dextrolateralview.(C)Habitus,without right sideappendages,frontalview.(D)Body,ventralview.(E) RightCx IIIIV,dorso-lateral view.(F)Same,magnified.Scale bars:A-D= 500μm;E = 200μm;F = 100μm.

Figure 4. Bunostigma singulare Mello-Leitão, 1935,male (MNRJ 7679),right legs I to IV,prolateral view.(A) Leg I. (B) Leg II. (C) Leg III. (D) Leg IV.(E)Ta I. (F) Ta II. (G) Ta III. (H)Ta IV.Scale bars:A-D = 500 μm; E-H = 100 μm.