Lacronia nigra (Mello-Leitão, 1923) Carvalho & Kury, 2023

Carvalho, Rafael N. & Kury, Adriano B., 2023, Between areolated and band-shaped spots: a revision of Lacronia Strand, 1942 (Opiliones, Gonyleptidae), European Journal of Taxonomy 859, pp. 1-56 : 33-39

Lacronia nigra (Mello-Leitão, 1923) comb. nov.

Figs 3A–D , 4F , 9B , 12–13 ; Table 5

Discocyrtus niger Mello-Leitão, 1923b: 125 , fig. 8.

Discocyrtus fazi Piza, 1942: 388 , fig. 2. Syn. nov.

Discocyrtus rarus B. Soares, 1944b: 297 , figs 7–8. Syn. nov.

Discocyrtus niger – Roewer 1929: 208, fig. 10. — Mello-Leitão 1932: 180, fig. 102; 1937: 289. — B. Soares 1946: 518. — Soares & Soares 1945: 340, fig. 2; 1954: 253. — Kury 2003a: 164.

Discocyrtus fazi – B. Soares 1946: 515. — Soares & Soares 1954: 249. — Cekalovic 1985: 17. — Kury 2003a: 163.

Discocyrtus rarus – B. Soares 1946: 518. — Soares & Soares 1954: 254. — Kury 2003a: 165.

Diagnosis

Lacronia nigra comb. nov. can be differentiated from the other species of the genus by the following combination of characters: 1) mesotergum areas I–IV with areolate spots around the ordinary tubercles ( Figs 3A–D , 4F , 12A ); 2) free tergites I–III with areolate spots around the paramedian pair of prominent tubercles ( Figs 3A–C , 4F , 12A ); 3) Ti III retro-ventral face with a comb of three spines (iIi) on the distal third ( Fig. 12D ); 4) Cx IV prodorsal apical apophysis with a spine on its distal apex ( Fig. 12A, E–F ); 5) Tr IV prolateral distal portion with a hook-shaped apophysis ( Fig. 12G–H ); 6) Fe IV short, approximately the same length as mesotergum ( Fig. 3A ); 7) Mt IV dorsal face with a row of prominent tubercles on proximal ⅔ ( Fig. 12K ).

Type material

CHILE • 1 ♀, holotype of Discocyrtus fazi Piza, 1942 ; MZSP 1549ꜝ (examined) (doubtful record, see remarks section below) .

BRAZIL • 1 ♀, holotype of Discocyrtus niger Mello-Leitão, 1923 ; state of Rio de Janeiro, “Pinheiro” [Piraí, Pinheiral]; MZSP 502ꜝ (not examined) • 1 ♂, holotype of Discocyrtus rarus B. Soares, 1944 ; State of São Paulo, Alto da Serra ; MZSP 706ꜝ (examined) .

Additional material examined

BRAZIL – State of São Paulo • 1♂; Cotia, Reserva Florestal Morro Grande–Torres ; 15 Jul. 2006; R. Pintoda-Rocha et al. leg.; MZSP 27935ꜝ • 1 ♂, 2 ♀♀; Cubatão , COPEBRAS; 22 Oct. 2004; C. Bragagnolo et al. leg.; MZSP 31869ꜝ • 6 ♂♂, 10 ♀♀; Cubatão, Trilha Cachoeira ; 2 Dec. 2004; C. Bragagnolo et al. leg.; MZSP 31871ꜝ • 1 ♂, 2 ♀♀; Itanhaém, Cidade Santa Júlia ; 30 Dec. 1978; L.R. Fontes and P.S. Terra leg.; MZSP 25146ꜝ • 5 ♂♂, 4 ♀♀; Santo André, Estação Biológica Paranapiacaba ; 2 May 1999; G. Machado leg.; MZSP 28540ꜝ • 1 ♂; Santo André, Paranapiacaba ; 18 Oct. 1952; Werner leg.; MNRJ 36ꜝ • 1 ♂; Santo André, Reserva Biológica do Alto da Serra [de Paranapiacaba]; 9 Sep. 1982; A. Cardoso, O.L. Peixoto and C.A.G. Cruz leg.; MNRJ 9207ꜝ • 1 ♂; same collection data as for preceding; 15 Oct. 1952; W. Bocherman leg.; MNRJ-HS 567ꜝ • 2 ♂♂; Santo André, Alto da Serra ; 12–16 Apr. 2019; L.N. Ázara et al. leg.; MNRJ 60385 • 1 ♂; Santo Antônio do Pinhal, Eugênio Lefévre ; 30 May 2009; R. Pinto-da-Rocha et al. leg.; MZSP 31070 • 2 ♂♂, 2 ♀♀; Santos, Vale do Rio Jurubatuba, margem direita, Trilha 1; 4 Oct. 2007; C. Bragagnolo et al. leg.; MZSP 31887ꜝ • 2 ♂♂, 1 ♀; same collection data as for preceding; MZSP 31889ꜝ • 5 ♂♂, 1 ♀; same collection data as for preceding; 21 Mar. 2007; A. Nogueira leg.; MZSP 31883 • 1 ♂, 1 ♀; São Bernardo do Campo, Parque Estoril ; 5–10 Apr. 2006; B. Tavora et al. leg.; IBSP 8853 .

Redescription

Male

MNRJ 60385 for the external body illustrations and description; MNRJ 9207ꜝ for genitalic illustrations.

MEASUREMENTS. DS: CW 2.7, CL 1.9, AW 5.1, AL 3.0; legs I–IV measurements in the Table 5 ; right / left tarsal (distitarsal) counts: 6(3) / 6(3) – 10(3) / 9(3) – 7 / x - 7 / 7.

DORSUM. DS gamma-pyriform, longer than wide, with lateral borders of the AS convex, widest at area II and thickest at area III, with a slightly convex posterior border ( Fig. 12A, E ). DS anterior border with a set of five acuminated tubercles, divided by a small central projection and a pair of shallow cheliceral sockets ( Fig. 12A ). Carapace with a paramedian pair of prominent tubercles posterior to the ocularium, surrounded by many ordinary tubercles lateral- and posteriorly ( Fig. 12A, E ). Ocularium elliptic (in dorsal view), high (ca 3× the eye diameter), almost forming a 90º angle in relation to the DS, placed in the anterior portion of the carapace ( Fig. 12A–B, E ). Ocularium with a pair of divergent spines (ca 2.5× the eye diameter), slightly inclined frontwards ( Fig. 12A–B, E ). Mesotergum divided in four clearly defined areas ( Fig. 12A, E ). Mesotergum areas I and IV divided into left and right halves by a longitudinal median groove ( Figs 4F , 12A ). AS lateral borders with a row of three prominent tubercles ( Fig. 12A ).All areas tuberculate, with almost all tubercles individually covered and surrounded by light colored spots ( Figs 3A–B , 4F , 12A ). Mesotergum area I with a pair of prominent tubercles ( Fig. 12A ). Mesotergum area II with a transversal row of prominent tubercles on the central portion ( Fig. 12A ). Mesotergum area III with a pair of paramedian outstanding spines (ca 3× the ocularium spines) ( Fig. 12A, C, E ). Mesotergum area IV with with a transversal row of tubercles bearing six to seven prominent tubercles ( Fig. 12A, E ). DS posterior border with a transversal row of prominent tubercles, the central pair largest and covered/surrounded by light colored spots ( Figs 3A–C , 4F , 12A ). Free tergites I–III each with a transversal row of prominent tubercles, central pair covered/surrounded by light colored spots ( Figs 3A– C , 4F , 12A ). Anal operculum tuberculate.

VENTER. Cx I–III sub-parallel to each other, each with ventral longitudinal rows of 8–12 setiferous tubercles (Cx I rows with higher and sharper tubercles than the others). Cx II–III with a retro-ventral distal row of acuminate tubercles. Cx IV much larger than the others, directed obliquely. Intercoxal bridges well-marked. Stigmatic area Y-inverted-shaped, clearly sunken in relation to the Cx IV distal part. Cx IV covered by ordinary tubercles. Cx IV posterior border and stigmatic area each with a transversal row of ordinary tubercles. Stigmata visible. Free sternites with a transverse row of ordinary tubercles.

CHELICERA. Basichelicerite elongate, bulla well-marked, with marginal setiferous tubercles – one mesal, one ectal, one posterior ( Fig. 12A ); hand not swollen.

PEDIPALPS. Tr with two geminate ventral setiferous tubercles. Fe with a ventral basal and a mesal apical setiferous tubercle. Pa unarmed. Ti with two rows (ventro-mesal and ventro-ectal) of four spines (IiIi). Ta with two rows of spines: three (iII) ventro-mesal and four (iIII) ventro-ectal.

LEGS. All the unmentioned podomeres are unarmed or without relevant armature. Tr I–III each with several ventral tubercles. Fe I sub-straight; Fe II straight; Fe III sinuous ( Fig. 12D ). Fe and Ti I–III with all faces containing longitudinal rows of small tubercles ( Fig. 12D ); Fe II–III with an apical retro-dorsal spur ( Fig. 3A–B ). Fe III with an apical prodorsal spur (reduced when compared to the retro-dorsal spur) ( Fig. 12D ). Fe III and Ti III with two rows (proventral and retro-ventral) of small acuminate tubercles, distally presenting spines (outstanding spines on Ti III) ( Fig. 12D ). Pa I–III covered dorsally by tubercles ( Fig. 12D ). Ti III mace-shaped ( Fig. 12D ). Cx IV reaching as far as the mesotergum area IV ( Fig. 12A ). Cx IV tuberculate between prodorsal and ventral faces ( Figs 3D , 12A ). Cx IV with a prolateral distal, thick cylindrical apophysis (distally curved backwards, bearing a conical spine on the apex), posteriorly crenated ( Fig. 12A, E–F ). Cx IV with a retro-lateral spiniform apophysis, fused with a small secondary branch ( Fig. 12A ). Tr IV square-shaped in dorsal view ( Fig. 12A, G, I ). Tr IV proximal portion with a conical apophyses on prolateral and retro-lateral faces (prolateral largest, retro-lateral slightly curved to dorsal on the distal portion) ( Fig. 12A, G–J ). Tr IV with a hook-shaped prolateral distal apophysis ( Fig. 12A, G–H ). Tr IV with a retro-lateral subconical distal apophysis ( Fig. 12G, I–J ). Tr IV ventral face tuberculate ( Fig. 12H–J ). Fe IV almost straight (in dorsal view), slightly arched on the central portion towards retro-dorsal face ( Fig. 12G–J ). Fe IV dorsal face with a row of five subconical outstanding tubercles on basal ⅔, with a conical tubercle on the distal apex ( Fig. 12G–H, J ). Fe IV prodorsal face with a row of seven outstanding subconical tubercles and a sizeable distal spur ( Fig. 12G–H ). Fe IV prolateral face with a row of four subconical tubercles on the proximal third and two prominent tubercles on the central third ( Fig. 12G–I ). Fe IV proventral face with a row of three subconical tubercles on the centraldistal portion and a sizeable distal spine ( Fig. 12H–I ). Fe IV ventral with a row of five prominent tubercles, which turns to the retro-ventral face with three prominent tubercles, a subconical outstanding tubercle and a sizeable distal spine ( Fig. 12I ). Fe IV retro-lateral face with a row of two prominent subconical tubercles, one spine on the proximal half, and two outstanding spines on the distal half ( Fig. 12G, I–J ). Fe IV retro-dorsal face with a row of ordinary tubercles on basal ⅔ and a spine and a sizeable spur on the distal third ( Fig. 12G, J ). Pa IV dorsally covered by sub-conical or acuminated prominent tubercles ( Fig. 12G–H, J ). Pa IV proventral face with a row of four spines (iiiI) ( Fig. 12H–I ). Pa IV retro-ventral face with two spines (II) ( Fig. 12I–J ). Ti IV dorsally covered by tubercles, with subconical outstanding tubercles and spines on the proximal half ( Fig. 12G–H, J ). Ti IV proventral face with a row of 11 spines, the two distalmost much larger than others ( Fig. 12H–I ). Ti IV retro-ventral face with a row of five prominent subconical tubercles and three distal outstanding spines (two distalmost largest) ( Fig. 12I–J ). Mt IV dorsal face with a row of prominent tubercles on the basal ⅔ ( Fig. 12K ).

COLOR (in vivo) ( Fig. 3A–D ). Ocularium, carapace, external portions of mesotergum areas I–II, AS lateral borders and Cx IV Dark Red (16). Mesotergum Reddish Black (24) with areolate spots Brilliant Orange Yellow (97) on mesotergum areas I–III and Dark Greenish Yellow (103) on mesotergum area IV. Proximal portion of the spines on mesotergum area III’s and AS posterior border Dark Olive Brown (96). Free tergites I–III background Deep Brown (56). Paramedian pair of prominent tubercles on AS posterior border and free tergites I–III and Fe II–III retro-dorsal spur Moderate Greenish Yellow (102). Ch and Pp background Grayish Olive Green (127), with honeycombed Dark Grayish Olive Green (128) reticle. Tr I background Moderate Greenish Yellow (102) and Moderate Olive (107). Tr II–III background Deep Yellowish Brown (75). FeMt I–III background Dark Grayish Olive (111). Fe–Mt IV background Dark Reddish Brown (44). The apex of the spines on DS area III and apex of the apophyses on Cx and Tr IV Dark Reddish Orange (39). Tips of tubercles and spines on Fe–Mt IV Deep Orange (51).

MALE GENITALIA. VP slightly divided into a distal half forming a rectangle with latero-apical flaps and a proximal half elliptical ( Fig. 13A, C ). VP ventral surface entirely covered with microsetae of type 1. All macrosetae inserted on the laterals of VP. MS A1–A3 cylindrical, thick, and acuminate, forming a triangle (A1 on the basal portion of the distal part, A2–A3 on the proximal part, A2 placed dorsalmost) ( Fig. 13A–C ). MS B1 small, inserted ventrally, close to A2 ( Fig. 13B–C ). MS C1–C3 similar to MS A, forming a row inserted on the ventral border (C3 dorsalmost) on the distal third of VP ( Fig. 13A–C ). MS D1 small, inserted on VP’s ventral border, close to C3 ( Fig. 13A–B ). MS E1–E2 small, inserted on the distal flange of VP – E1 between MS C1–C2, E2 below C3 ( Fig. 13A–B ). Glans sac arising from the middle bulge on the podium, not extended as a dorsal process ( Fig. 13A–B ). Stylus and its ventral process axis fused basally, forming a prominent pedestal ( Fig. 13A–B ). Stylus cylindrical, almost straight (apex slightly bent ventrally), inserted on a pedestal forming a 45º angle, without a conspicuous head and armed with a few small sub-distal tiny spines ( Fig. 13A–B ). Ventral process is ¾ of the stylus length, slightly bent dorsally, with an apical flabellum curved ventrad ( Fig. 13A–B ). Flabellum scallop-shaped with serrulations, with approximately 35% of the ventral process stem length ( Fig. 13A–B ).

Female (MZSP 1549ꜝ) ( Fig. 9B )

DS, measurements: CW 2.3, CL 1.6, AW 4.0, AL 2.7; Fe I–IV measurements: I = 1.73, II = 3.13, III = 2.36, IV = 2.87; right / left tarsal (distitarsal) counts: 6(3) / 6(3) - x / x - x / 7 - x / 7.

DS gamma type. Cx IV narrower than in males, with the prodorsal apophysis reduced to a single spine and retro-lateral distal portion unarmed. Tr IV prolateral face unarmed. Tr IV retro-lateral proximal apophysis as a tiny spine. Tr IV retro-lateral distal apophysis as a prominent conical spine, slightly curved dorsally. Fe IV thinner than in male, with armature reduced to a prominent spine on the distal third and a pair of dorso-distal spurs (retro-dorsal largest). Mt IV dorsally covered by ordinary tubercles.

Intraspecific variation

In the minor morph males (compared to major morph): DS narrower; Cx IV with reduced prolateral and retro-lateral apophyses; Fe IV is thinner, with reduced armature size. It was not found intraspecific variation among the major morph males or among females.

Historical taxonomic remarks

The female holotype of Discocyrtus niger (recognized here as Lacronia nigra comb. nov.), recorded as specimen MZSP 502, was not found during this study. However, its morphology (after reviewing the original description and illustration, especially referring to the large retro-lateral distal apophysis on Tr IV) is identical to the females of Discocyrtus rarus . The type locality of L. nigra comb. nov. (Pinheiral, Piraí, Rio de Janeiro) is congruent with the current geographical occurrences of D. rarus ( Fig. 14 ), especially because there is a record by Soares & Soares from Seropédica, which is quite close to Piraí (40 km in a straight line). Therefore, D. rarus is considered here a subjective junior synonym of L. nigra comb. nov.

Discocyrtus fazi was described by Piza (1942) based on the female holotype (MZUSP 1549ꜝ), in a paper focused on Chile’s diversity of Opiliones . The type locality of D. fazi was reported as Chile ( Fig. 14 ), without any additional data. There are no other recorded specimens of D. fazi , either nominal or of something that could be interpreted as this species, since its description, in spite of several authors reviewing the Chilean opilionofauna (e.g., Pérez-Schultheiss 2021). The holotype of D. fazi is a perfect match to all the females assigned here as L. nigra comb. nov. This unlikely record could be a result of a mislabeling by Piza, who mostly worked with the material of Opiliones from São Paulo throughout his career. According to this scenario, 1) D. fazi is herein considered a junior subjective synonym of L. nigra comb. nov., and 2) its record from Chile is considered incorrect. Therefore, this revision of Lacronia unveils a previously undetected monophyletic group in one hand, helping to depurate the polyphyletic Pachylinae, while on the other hand allowing for a gradually clearer concept of Discocyrtus , both morpho- and geographically.

Records

BRAZIL, state of Rio de Janeiro: Seropédica ( Soares & Soares 1945). State of São Paulo: [Monte Alegre], Três Pontes ( Mello-Leitão 1937).

Geographic distribution (new records with an asterisk)

BRAZIL: state of Rio de Janeiro: Piraí, Seropédica. State of São Paulo: Alto da Serra, Cotia*, Cubatão*, Itanhaém*, Monte Alegre, Santo André*, Santo Antônio do Pinhal*, Santos*, São Bernardo do Campo* ( Fig. 5 ).

Figures

Fig. 3. Lacronia spp., specimens in vivo. A–D. L. nigra (B. Soares, 1942) comb. nov., ♂, from Brazil, São Paulo, Santo André, Alto da Serra. E–H. L. tenuis (Roewer, 1917) comb. nov., ♂, from Brazil, Rio de Janeiro, Mangaratiba. Source: Adriano Kury.

Fig. 4. Lacronia spp., schematic illustrations of the ♂ DS, showing the background variation and tubercles patterns of the specimens in vivo (except for L. boraceae (B. Soares, 1942) comb. nov., which information was only available in alcohol). A. L. ceci Kury & Orrico, 2006. B. L. camboriu Kury, 2003. C. L. ricardoi Kury, 2003. D. L. serripes (Mello-Leitão, 1923). E. L. boraceae comb. nov. F. L. nigra (B. Soares, 1942) comb. nov. G. L. tenuis (Roewer, 1917) comb. nov. Scale bars = 1 mm.

Fig. 9. Lacronia spp., female specimens, dorsal habitus. A. L. boraceae (B. Soares, 1942) comb. nov., holotype (MZSP 114ꜝ), schematic illustration. B. L. nigra (Mello-Leitão, 1923) comb. nov., holotype of Discocyrtus fazi Piza, 1942 (MZSP 1549ꜝ), schematic illustration. C. L. serripes Mello-Leitão, 1923 (MZSP 9973). Scale bars = 3 mm.

Fig. 12. Lacronia nigra (B. Soares, 1942) comb. nov., ♂ (MNRJ 60385). A. Habitus, dorsal view. B. Ocularium, frontal view. C. Armature of mesotergum area III, posterior view. D. Fe–Ti III, prodorsal view. E. Habitus, lateral view. F. Detail of the Cx IV prodorsal distal apophysis, posterior view. G. Right Fe–Ti IV, dorsal view. H. Same, prolateral view. I. Same, ventral view. J. Same, retro-lateral view. K. Right Mt–Ta IV, retro-lateral view. Scale bars: A, D–E, K = 2 mm; B–C, F = 1 mm; G–J = 3 mm.

Fig. 13. Lacronia nigra (B. Soares, 1942) comb. nov., ♂ (MNRJ 9207ꜝ), penis, distal part. A. Dorsal view. B. Lateral view. C. Ventral view. Scale bars = 20 μm.

Fig. 14. South America, showing the distribution of the Lacronia nigra (B. Soares, 1942) comb. nov. non-type specimens (as white circles). The legend refers to the type localities of Discocyrtus niger B. Soares, 1942 (Piraí) and Discocyrtus rarus B. Soares, 1944 (Alto da Serra). The area shaded in magenta represents Chile, the type locality of Discocyrtus fazi Piza, 1942.

Fig. 5. Southeasten and Southern regions of Brazil, showing the distribution of the Lacronia spp. The area shaded in green represents the Atlantic province, as proposed by Morrone et al. (2022).