Eusarcus signatus (Roewer)

Hara, Marcos Ryotaro & Pinto-Da-Rocha, Ricardo, 2010, Systematic review and cladistic analysis of the genus Eusarcus Perty 1833 (Arachnida, Opiliones, Gonyleptidae) 2698, Zootaxa 2698, pp. 1-136: 101-103

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Eusarcus signatus (Roewer)

comb. n.

Eusarcus signatus (Roewer)   comb. n.

( Fig. 32)

Antetriceras signatus Roewer 1949: 57   , fig. 111a–d; Kury 2003a: 156 (cat); 2003b: 6 (syst); (ma holotype; "Terra Vermelha, Rio de Janeiro; SMF RII 5078/12"; examined, without genitalia, spine of ocularium broken).

Material examined: BRAZIL. Rio de Janeiro   : Rio de Janeiro? (Terra Vermelha), without name of collector and date, ma holotype ( SMF RII 5078 /12)   .

Diagnosis: E. signatus   resembles E. aduncus   , E. berlae   , E. elinae   , E. fulvus   , E. sooretamae   , E. cavernicola   , E. mirabilis   and E. sergipanus   because of the conical prolateral median apophysis on the male trochanter IV, and can be distinguished by: The presence of PAM; median spine of scutal area III of medium size; basitarsus I not elongated; prolateral apical apophysis of the male coxa IV with triangular ventral projection; femur IV not longer than 1.5 times dorsal scutum length, with 1 PVS and a large retrolateral apical tubercle; ocularium with a median spine.

Redescription: Male (holotype): Dorsum ( Fig. 32A,B): Measurements: SL 2.80; SMW 2.50; femur I 1.50; II 3.00; III 2.20; IV 2.70. Median paracheliceral projection of similar-size as PAM. Ocularium far from anterior scutal margin; with a median spine, 6 tubercles. Carapace with 23 scattered tubercles. Scutal area I with 13–14 scattered tubercles on each side; II with 28; III with 27 and a median spine of medium size, reaching groove V; IV with 21 tubercles. Posterior margin of dorsal scutum with 7 scattered tubercles and a row of 13 tubercles. Free tergites I–III with a row of 9, 8, 9 tubercles, respectively. Anal operculum with 14 tubercles.

Venter: Coxa I with 20 tubercles, median and distal ones largest; II–III with 31–37 and 26–36, respectively, increasing in size distally; IV irregularly tuberculate.

Chelicera: Segment I smooth.

Pedipalpus: Trochanter dorsally inflated, with 2 tubercles. Femur dorsally with small, scattered tubercles; ventrally with 2 scattered tubercles. Tibial setation: Prolateral and retrolateral IiIi. Tarsal setation: Prolateral iiIi/iIi, retrolateral IiIi.

Legs ( Fig. 32C–F): Coxa II with 1–2 tubercles on retrolateral margin; IV densely tuberculate, ending between grooves III and IV of dorsal scutum, surpassing dorsal scutum in dorsal view only apically, with 1 transversal prolateral apical apophysis, this conical, short, blunt, with 1 triangular ventral projection and another one, transversal, in the middle. Trochanters I–IV with scattered tubercles; I with 1 large ventro-basal tubercle; III with 1 large retrolateral apical tubercle; IV prolaterally with 1 median apophysis, this conical, curved anteriad; retrolaterally with 1 short, pointed apical apophysis. Femur I with reduced PDS, RDS; II–III with reduced PDS, medium RDS; III sinuous, ventrally with a prolateral row of tubercles slightly increasing in size distally, 1 large prolateral apical tubercle; IV sinuous, with medium PDS, RDS; ventrally with 2 rows of tubercles increasing in size distally, prolateral ones enlarged, 1 prolateral apical apophysis, 1 large retrolateral apical tubercle. Tarsal segmentation: 6, 8–9, 6, 6.

Coloration: Brown; dark brown on prosoma and leg IV.

Female: Unknown.

Taxonomical note: Kury (2003b) suggested an affinity between the genera Antetriceras Roewer 1949   (here placed in the synonymy of Eusarcus   ) and Pherania Strand 1942   on the basis of descriptions and illustrations of A. signatus   . Unfortunately, illustrations of apophyses as well as the width of coxa IV provided by Roewer were inaccurate. Thus Kury (2003b) was misled to propose an unlikely association. Although no member of Pherania   was included in any cladistic analysis, it is improbable that this genus is closely related to Antetriceras   , since the former does not have the synapomorphies of Eusarcus   , such as a median spine in scutal area III or a paramedian pair of apophyses placed ectally to the chelicera on the anterior margin of the dorsal scutum.

Type locality: Brazil, Rio de Janeiro, Rio de Janeiro (?). Precising the exact type locality of this species is a difficult task. When Roewer described the species, he only stated “Terra Vermelha”, a very common name that occurs in many places of   Brazil. On the basis of the localities and information from the collector, Kury (2003a) gave “ Santa Catarina, Seara, Terra Vermelha” as the type locality. However , we verified that it is clearly written “ Rio de Janeiro ” on the label of the holotype. Although risky, considering the distribution of species closely related to A. signatus   , we suggest the city of Rio de Janeiro as the probable exact locality   .

Geographical distribution: Known only from the type locality.


Forschungsinstitut und Natur-Museum Senckenberg














Eusarcus signatus (Roewer)

Hara, Marcos Ryotaro & Pinto-Da-Rocha, Ricardo 2010

Antetriceras signatus

Kury, A. B. 2003: 156
Roewer, C. F. 1949: 57