Cryptocellus iaci, Tourinho, Ana Lúcia, Lo, Nancy F. & Bonaldo, Alexandre Bragio, 2010

Tourinho, Ana Lúcia, Lo, Nancy F. & Bonaldo, Alexandre Bragio, 2010, A new species of Ricinulei of the genus Cryptocellus Westwood (Arachnida) from northern Brazil, Zootaxa 2684, pp. 63-68 : 64-67

Cryptocellus iaci sp. nov

( Figs 1–12 )

Type material. Female holotype ( INPA 086), Brazil, state of Roraima, municipality of Caracarai, community of Caicubi, 01°00΄32,0 4ʺN 62°07΄10,56ʺW, 25 Oct. 2008, visual nocturnal search, A.L. Tourinho leg.

Etymology. A noun in apposition. In Tupi, Iaci means moon or mother of fruits, here used in reference to the Amazonian mythology of “ Icamiabas ”, the female warriors described in the chronicles of the Dominican friar Gaspar de Carvajal. According to this myth the brave “ Icamiabas ” would annually meet the males from the tribe Gacaris for a mating night called the “ Iaci ” party.

Diagnosis. C. iaci sp. nov. can be readily recognized by the following combination of characters: carapace virtually smooth ( Figs. 7, 8 differing from females of C. ababoru , C. becki , C. foedus and C. simonis , which have tuberculate carapaces); proximal apophysis present dorsally on femora of legs I and II ( Figs. 1 , 9 ), blunt and as long as wide; proximal apophysis size similar to C. abaporu but not rounded as in that species (see Bonaldo & Pinto-da-Rocha 2003: fig.14). The new species resembles C. becki (see Platnick & Shadab 1977: fig. 38) in having few tubercles on the cucullus, concentrated in the proximal region ( Fig. 10 ), but differs by having the opisthosoma with two ventral pairs of shallow lateral pits containing tubercles, anterior pair smaller than the other ( Fig. 11 ). Spermathecae similar to those of C. simonis , but with more highly coiled ducts ( Figs. 13, 14 ).

Description of female holotype. Total body length, excluding pygidium, 5.11, cucullus 0.88 long, greatest width 1.22, prosoma 1.96 long, 1.81 wide between legs II and III; opisthosoma 3.14 long; 2.59 wide near middle of tergite; legs I 4.62, II 7.40, III 5.18, IV 6.51. General body color (in 80% ethanol) dark reddishbrown, opisthosoma lighter than carapace, ventral opisthosoma lighter than dorsal, intersegmental membranes orange; cucullus dark red, much darker at anterior margin and in median half. Few rounded tubercles only at margins of prosoma, no tubercles in median portion ( Figs. 7, 8 ); cucullus with few tubercles, concentrated proximally, very few and sparse distally, distal margin of lateral lobes slightly protuberant ( Fig. 10 ); opisthosomal tubercles spread on lateral tergites, only present on posterior half of opisthosoma, mostly concentrated in lateral concavity and at posterior margin, no median tubercles, intersegmental membranes without tubercles or setae ventrally; legs covered with tubercles dorsally, ventrally concentrated in posterior half. Iridescent tubercles, showing shades of purple and dark blue, present on: dorsal cucullus, opisthosoma (more numerous), and legs, sparse in all dorsal and lateral parts of legs, but more numerous on distal part of trochanter ( Fig. 4 ) and proximal part of patella. Surface of body entirely covered by two types of white setae, short and curved ( Fig. 2 ) or long and straight ( Fig. 3 ). Prosoma longer than wide ( Fig. 8 ), distal margin with few long and short setae; cucullus as long as wide ( Fig. 10 ) with greater concentration of long, straight setae; opisthosoma with greater concentration of short, curved setae, appendages with long, straight setae predominating over short ones. One pair of lateral “eyes” ( Fig. 8 ). Cheliceral movable fingers armed with seven (left chelicera) or eight (right chelicera) teeth of similar size, fixed fingers with five teeth (both chelicerae), Sternal region with coxa I not meeting tritosternum; left and right coxae II–III meeting; coxae IV meeting anteriorly; midline suture of coxae II slightly longer than those of coxae III and IV. Pygidium with distal dorsal notch on basal segment; no ventral notch ( Fig. 12 ). Pedipalps orange, without tubercles. Leg formula II>IV>III>I. Spermathecae wider than long, with highly coiled ducts; genital lip narrow, folded posteriorly ( Figs. 13, 14 ).

Male. Unknown.

Distribution. Known only from the type locality in northern Brazil.

Remarks. The only species of Cryptocellus from northern Brazilian Amazonia for which females are unknown is C. icamiabas , described from Balbina, Presidente Figueiredo, nearly about 441 km west of the type locality of C. iaci sp. nov. The female described here cannot be assigned to C. icamiabas because of conspicuous morphological differences that could hardly be ascribed to sexual dimorphism: C. iaci sp. nov. has a smaller number of tubercles on the cucullus and on the median plate of tergite XI, and lacks the large posterior pair of ventral opisthosomal pits (see Tourinho & Azevedo 2007: fig. 3). The new species presents blunt, distally enlarged setae on the carapace, cucullus, prosoma and legs. SEM photographs ( Figs. 5, 6 ) of these swab-like setae suggest that this shape is produced by clay accumulation on the apex of each setae. Similar setae are reported to be present in at least one other species, C. tarsilae (see Pinto-da-Rocha & Bonaldo 2007).

Notes on the biotope. The inventory was carried out at Caicubi, Jauaperí River, state of Roraima, Brazil. Jauaperí is a black-water river (water with low concentration of nutrients), which flows through the south and meets with the median Negro River. Along the Jauaperí and its affluent there are primary forests of “igapó” (black-water flooded forests).

Negro River is one of the largest tributaries of the Amazon River and one of the largest rivers in the world ( Franzinelli & Igreja 2002; Latrubesse & Franzinelli 2005). The Negro basin drains an area of more than 600000 km 2 and extends through parts of Colombia, Venezuela and Brazil ( Latrubesse & Franzinelli 2005). The Negro River is constrained by several tectonic influences ( Franzinelli & Igreja 2002; Latrubesse & Franzinelli 2002; 2005; Albert et al. 2006). One important tectonic event occurred in the Vaupés arc (northwestern Amazonian), located in the headwaters of the Negro River, which caused the separation between the Orinoco and Amazon Basins ( Hoorn 1993; Figueiredo et al. 2009).

The waters of the Negro River have high concentrations of dissolved humic acids (from organic material, such as roots, leaves and wood, that decays slowly in the water) and iron oxides, which give the water its characteristic acid pH. Such rivers are commonly called black-water ( Franzinelli & Igreja 2002), in distinction to rivers with basic pH, called white-water rivers (e.g. Amazonas river). From an ecological point of view, the concentrations of nutrients in the water of Amazonian rivers have both direct and indirect effects on the alpha and beta species diversity, also affecting the distribution of species (see Albernaz 2007).

This Jauaperi region is under high ethnological and environmental risk, so that NGO WWF-Brazil, the Program for Protected Amazonian Areas (ARPA), the Amazonas State Government, Chico Mendes Institute for Conservation of Biodiversity (ICMBio) and the National Indigenous Foundation (FUNAI) are working together to establish protected areas in this important region.

Figures

FIGURES 1 – 6. Cryptocellus iaci sp. nov., female holotype, leg I. 1, femur, showing apophysis and two types of white setae, prolateral view; 2, femur, white setae, long and straight, ventral view; 3, femur, white setae, short and curved, ventral view; 4, trochanter, tubercles, lateral view; 5, patella, detail of white setae and blunt, distally enlarged setae, ventral view; 6, patella, swab-like setae, lateral view.

FIGURES 7 – 12. Cryptocellus iaci sp. nov., female holotype. 7, habitus, dorsal view; 8, carapace, dorsal view; 9, femur II, prolateral view, showing apophysis; 10, anterior view, showing cucullus; 11, body, ventral view; 12, opisthosoma, dorsal view. Scale bars: 7 = 2.0 mm; 8 – 10 = 0.5 mm; 11 – 12 = 1.0 mm.

FIGURES 13 – 14. Cryptocellus iaci sp. nov., female holotype, spermathecae. 13, posterior view; 14, anterior view. Scale bars: 0.25 mm.