Metalibitia argentina ( Sørensen, 1884 ),

Coronato-Ribeiro, Amanda & Pinto-Da-Rocha, Ricardo, 2017, Taxonomic revision and cladistic analysis of the genus Metalibitia Roewer, 1912 (Opiliones, Cosmetidae, Cosmetinae), Zootaxa 4291 (2), pp. 201-242: 213-217

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Metalibitia argentina ( Sørensen, 1884 )


Metalibitia argentina ( Sørensen, 1884) 

(Figs: 1B; 3A; 5B, F; 7B, F; 11A –C)

Cosmetus argentinus Sørensen, 1884: 593  [desc]; Kury, 2003: 68 [cat].

Cosmetus Argentinus  : Sørensen, 1895: 1 [cit]; Moritz, 1971: 191 [cit]; Kury, 2003: 68 [cat].

Paralibitia argentina: Roewer, 1912: 14  [cit]; 1923: 295 [rdesc]; 1927: 552 [cit]; Mello-Leitão, 1932: 90 [rdesc]; 1933: 109 [syst]; Moritz, 1971: 191 [cit]; Kury, 2003: 68 [cat].

Paralibitia maculata Roewer, 1914: 130  [desc], fig. 15; 1923: 295 [rdesc], fig. 316; 1927: 552 [key]; Mello-Leitão, 1932: 90 [rdesc], fig. 58; Weidner, 1959: 128 [cit]; Kury, 2003: 69 [cat]. New synonymy

Libitia (Messa) argentina: Sørensen, 1932: 412  [syst]; Kury, 2003: 68 [cat].

Labrosa arenosa Mello-Leitão, 1939: 294  [desc], fig. 17; Kury, 2003: 68 [cat] [syst]. New synonymy

Metalibitia maculata: Ringuelet, 1959: 425  [cit]; Kury 2003: 69 [cat]; Pinto-da- Rocha & Hara, 2011: 3 [cit].

Metalibitia argentina: Ringuelet, 1959: 418  [rdesc, syst, cit], fig 60; Valentinis de Martínez, 1974: 6 [cit]; Kury, 2003: 68 [cat].

Metalibitia arenosa: Kury, 2003: 68  [cat, syst].

Type material. Cosmetus argentinus  : ZMUC, ZMB 8391 syntypes ( Kury, 2003). Syntype ZMB 8391 examined From photo. M. maculata  : ERPC holotype; ZMH, SMF RI, paratypes. Paratype ♂ SMF examined. M. arenosa  : holotype ♂ with depository unknown.

Type locality. M. argentina  : ARGENTINA  , Buenos Aires Province, San Nicolas, Santa Fe Province , “on the way to Villa Hernandaria ” [Hernandarias], and Chaco Province , near “ Baranjeras ” [Barranqueras] ( Sørensen, 1884). M. maculata  : PARAGUAY, San Bernardino District   . M. arenosa  : BRAZIL, Mato Grosso do Sul State, Salobra River (20°11'S 56°31'W, 215 m).GoogleMaps 

Geographical distribution ( Fig. 14View FIGURE 14): Studied localities are restricted to northeastern Argentina  , provinces oF Chaco (Resistencia) and Buenos Aires (San Nicolas), western Paraguay (Rio Apa) and Department oF Cordillera (San Bernardino) and midwestern Brazil (Mato Grosso do Sul State).

Diagnosis. Resembles M. brasiliensis  in having retrolateral tubercles on middle region oF trochanter IV ( Figs 5View FIGURE 5 B, D, F, H) and M. borellii  in having Free tergite III with central tubercle larger than the others ( Figs 1View FIGURE 1 B, C); it recalls both species in having tibia IV unarmed ( Figs 7View FIGURE 7 B –D). Distinguished From the reFerred species in having median tubercles on trochanter IV spaced ( Figs 5View FIGURE 5 B, F) (in M. brasiliensis  these tubercles are placed close to each other, Figs 5View FIGURE 5 D, H; M. borellii  has one basal and one apical tubercle, Figs 5View FIGURE 5 C, G); also by central tubercles oF Free tergite III larger than the other ones ( Fig. 1View FIGURE 1 B) ( M. brasiliensis  has similar sized tubercles, Fig. 1View FIGURE 1 D), and Femur IV unarmed ( Figs 5View FIGURE 5 B, F) ( M. borellii  has an apical tubercle, Figs 5View FIGURE 5 C, G).

Redescription. Male (MACN 4497)

Measurements: dorsal scutum, total length 3.7; dorsal scutum, total width 3.9; prosoma length 1.4; prosoma width 2.2; Femur I length 1.7; Femur II length 2.8; Femur III length 2.5; Femur IV length 3.3; pedipalpal Femur length 0.8 mm.

Coloration in ethanol: Entirely pale brown, legs slightly lighter than dorsal scutum.

Dorsum ( Fig. 1View FIGURE 1 B): Median region oF anterior margin oF dorsal scutum smooth, two high and truncated tubercles near paracheliceral projections. Lateral margin oF opisthosoma with rounded tubercles on areas I –IV. Domed ocularium (i.e., without a median depression), with ten small tubercles. Scutal area IV with a pair oF paramedian small spines with rhomboid apex. Posterior margin oF dorsal scutum with a row oF 18 tubercles. Free tergite I with row oF 17 tubercles, II with row oF 13 tubercles, III with row oF eight tubercles, the median one larger than the others and Formed by three joint tubercles. Anal operculum with 18 irregularly scatterd tubercles. All tubercles oF posterior margin, Free tergites and anal operculum with rounded apex.

Chelicera ( Fig. 1View FIGURE 1 B): Bulla with Five rounded tubercles on proximal margin, one probasal tubercle (on leFt side), small lateral tubercles and two prolateral apical tubercles Fused. Finger oF segment II with Four teeth, segment III with Five teeth.

Pedipalps ( Fig. 3View FIGURE 3 A): Trochanter with two apical ventral tubercles united at the base. Femur with 12 dorsal setiFerous tubercles; dorsal prolateral row oF Four setiFerous tubercles; ventral row oF Five setiFerous elongated tubercles, being the median two larger than the others; three setiFerous ventroapical tubercles. Tibia with small dorsal setiFerous tubercles, a small prolateral apical rounded projection, one dorsoapical tubercle on each side, one ventral prolateral spine and a row oF seven ventral retrolateral setae. Tarsus with dorsal and lateral setae, Five prolateral ventral setae, Four retrolateral ventral setae and 11 ventral setae.

Legs ( Figs 1View FIGURE 1 B; 5B, F; 7B, F): Coxa I with one prolateral basal long FalciForm tubercle (reaching the coxa apex) and one smaller basal retrolateral tubercle. Coxa II with prolateral tubercle with rhomboid apex directed towards apex oF the coxa and one tubercle with rounded apex, smaller than retrolateral one. Coxa III with one prolateral tubercle. Coxa IV visible in dorsal view, tuberculated, with one dorso-apical apophysis and three retroapical ventral tubercles. Trochanter IV with small retrolateral tubercles, Four retroventral tubercles (two apical united at their base) and one ventroapical tubercle. Femur IV curved and entirely granulous, with tubercles more concentrated on dorso-retrolateral region. Patella and tibia IV tuberculate, with long tubercles on dorsal side. Tarsal Formula: 5 / 7 / 5 / 6.

Penis ( Figs 11View FIGURE 11 A –C): Truncus with truncated enlargement at the junction with ventral plate. Ventral plate with gentle concavity on distal margin, with two pairs oF micro-spines on ventrodistal region and one pair oF macrosetae E in median-ventral region. Five pairs oF macrosetae on median region to distal region oF ventral plate, two subapical pairs (macrosetae C), one dorso-median pair (macrosetae D), one lateral pair (macrosetae B) and one dorsobasal pair (macrosetae A). The membranous projection extended on the basal halF oF ventral plate. Insertion oF glans dorsally on middle oF ventral plate. Glans wide, slightly Flattened dorso-ventrally; base oF stylus narrowed. Stylus narrow, long, with thin and smooth apex.

Female (MACN 4496)

Measurements: dorsal scutum, total length 3.5; dorsal scutum, total width 3.2; prosoma length 1.1; prosoma width 1.7; Femur I length 1.6; Femur II length 2.9; Femur III length 2.2; Femur IV length 2.7; pedipalpal Femur length 0.7 mm.

Dorsum: Posterior margin oF dorsal scutum with a row oF 25 small tubercles, with rounded apex. Free tergite I with 22 tubercles, II with 16 tubercles, III with 10 similar sized tubercles. Anal operculum with 25 tubercles irregularly scattered. Pedipalps: Femur with dorsal proximal projection reaching the median region, Formed by small tubercles and Followed by three dorsoapical tubercles; ventral row oF six tubercles and two apicoventral tubercles. Legs: Coxae with small tubercles. Coxa IV with ventral region smooth. Trochanter IV smooth. Body entirely little tuberculated. Tarsal Formula: 5 / 7, 6 / 5 / 6.

Variation. Cheliceral bulla oF males can have 4 to 6 proximal tubercles. Tarsus oF pedipalp can have six prolateral spines and two retrolateral spines. Coxa III can have small retrolateral tubercle united to coxa IV. The trochanter IV can have up to Five retrolateral tubercles and up to one apical tubercle, the tubercles may or may not be arranged in a row. The ventral plate oF penis may have two pairs oF dorsal median macrosetae (group D). Measurements ♂ (n=4): dorsal scutum, total length 3.5–3.8; dorsal scutum, total width 3.4–3.8; prosoma length 1.1–1.2; prosoma width 1.9–2.2; Femur I length 1.6–2.1; Femur II length 3.1–4.0; Femur III length 2.6–3.2; Femur IV length 2.9–3.4; pedipalpal Femur length 0.7–0.9 mm. Measurements ♀ (n=3): dorsal scutum, total length 3.3– 3.9; dorsal scutum, total width 3.2–3.4; prosoma length 1.0–1.1; prosoma width 1.7–1.9; Femur I length 1.7–2.3; Femur II length 3.2–3.5; Femur III length 2.5–2.7; Femur IV length 3.0–3.2; pedipalpal Femur length 0.8–0.9 mm.

Synonymic note: Metalibitia maculata  was described based on one male and is hereby synonymized with M. argentina  based on morphological similarities: coxae I and II with retrolateral and prolateral tubercles, Free tergite III with median tubercles larger than the others, cheliceral bulla with two proapical tubercles Fused, trochanter IV with Four retroventral tubercles, the two apical Fused at their base, truncus oF penis with small enlargement at the junction with ventral plate, the latter with slight concavity on its distal margin, same number oF macrosetae groups A, B, C and E, glans elongated and wide. Variation in group D oF penis macrosetae was observed (unambiguous homoplastic synapomorphy, Fig. 15View FIGURE 15), may have two pairs oF dorso-median macrosetae. M. arenosa  was described based on one male specimen and is here synonymized with M. argentina  based on morphological similarities: presence oF a pair oF spines on area III, Free tergite III with median tubercle larger than others, absence oF subapical tubercle on Femur IV and trochanter IV with retrolateral tubercle, these Features are according to its original description ( Mello-Leitão, 1939), because the type material is lost. Both synonymized species have a similar or near geographical distribution to M. argentina  .

Material examined. ARGENTINA  . Chaco Province, Resistencia , 27°27'06.3"S 58°59'14.2"W, XII.1944, Cranwell leg., 1♂ 2♀ ( MACN 4496View Materials)GoogleMaps  ; same loc., 18/ 20.VI.1934, J.B. Daguerre leg., 3 ♂ (MACN 4497), same loc., 18.VIII.1955, J. B. Daguerre leg., 12♂ 24♀ (MACN 4499). PARAGUAY. Apa River , 22°06'21.2"S 56°30'30.9"W, no date, no leg., 2♂ ( SMF 5856View Materials /167); same loc.GoogleMaps  , Cordillera Departament, San Bernardino , 25°18′38″S 57°17′46″W, no date, no leg., 1♂ ( SMF 1075View Materials)GoogleMaps  .


Museo Argentino de Ciencias Naturales Bernardino Rivadavia


Forschungsinstitut und Natur-Museum Senckenberg














Metalibitia argentina ( Sørensen, 1884 )

Coronato-Ribeiro, Amanda & Pinto-Da-Rocha, Ricardo 2017

Metalibitia arenosa:

Kury 2003: 68

Metalibitia maculata:

Rocha 2011: 3
Kury 2003: 69
Ringuelet 1959: 425

Metalibitia argentina:

Kury 2003: 68
Martinez 1974: 6
Ringuelet 1959: 418

Labrosa arenosa Mello-Leitão, 1939 : 294

Kury 2003: 68
Mello-Leitao 1939: 294

Libitia (Messa) argentina: Sørensen, 1932 : 412

Kury 2003: 68
Sorensen 1932: 412

Paralibitia maculata

Kury 2003: 69
Weidner 1959: 128
Mello-Leitao 1932: 90
Roewer 1914: 130

Paralibitia argentina:

Kury 2003: 68
Moritz 1971: 191
Mello-Leitao 1932: 90
Roewer 1912: 14


Kury 2003: 68
Moritz 1971: 191
Sorensen 1895: 1

Cosmetus argentinus Sørensen, 1884 : 593

Kury 2003: 68
Sorensen 1884: 593