An unusual cryptogeobiid from southeastern Brazil revisited (Opiliones, Laniatores, Gonyleptoidea)

Adriano Brilhante Kury,Laura Regina Caramori

doi:10.11606/1807-0205/2021.61.94

Abstract

The monotypic genus Bunostigma Mello-Leitão, 1935 is herein revisited. A detailed redescription of its type-species, Bunostigma singulare Mello-Leitão, 1935 from Rio de Janeiro state, eastern Brazil, is herein presented, providing in depth knowledge of this genus. Bunostigma is most closely related to Cryptogeobius Mello-Leitão, 1935, and as this genus, it has a stout complex apophysis on male coxa IV, lacking, however, a second complex on the stigmatic area. Bunostigma has an oblique elongate malleus, similar to that of Zalanodius Mello-Leitão, 1936 (as opposed to a globular malleus in Cryptogeobius). Bunostigma singulare has short legs, with some sexual dimorphism on its stoutness, a dorsal scutum entirely unarmed and an ocularium with an accessory central mound, although unarmed.

Highlights

Amidst the soil-dwelling Neotropical harvestmen, the recently described family Cryptogeobiidae includes 55 valid species (Kury et al, 2021) distributed in the eastern Brazilian Atlantic Forest, extending somewhat to the interior to Paraguay (Kury, 2003)
Cryptogeobiids are small laniatorean Gonyleptoidea with male genitalia characterized by a hammer + lamina parva as opposed to other such as cosmetids and gonyleptids
Bunostigma singulare possesses (1) an unusual bicolor pattern of body, (2) a greatly developed retroventral apical apophysis on Cx IV which distorts overall outline of stigmatic area as to make it roughly triangular, (3) a stout Ti IV on male, armed with thick spiniform apophyses

Summary

INTRODUCTION

Amidst the soil-dwelling Neotropical harvestmen, the recently described family Cryptogeobiidae includes 55 valid species (Kury et al, 2021) distributed in the eastern Brazilian Atlantic Forest, extending somewhat to the interior to Paraguay (Kury, 2003). Bunostigma singulare possesses (1) an unusual bicolor pattern of body (in most cryptogeobiids, when the body is bicolor, the scutal areas are darker than the rest), (2) a greatly developed retroventral apical apophysis on Cx IV which distorts overall outline of stigmatic area as to make it roughly triangular (as opposed to T‐shaped in most members of the family), (3) a stout Ti IV on male, armed with thick spiniform apophyses. All those features set B. singulare apart from the run-of-the-mill Cryptogeobiidae.

MATERIAL AND METHODS

DISCUSSION