A new species of Andocaeculus ( Acari , Caeculidae ) from the Pampa biome , southern Brazil

A new caeculid species Andocaeculus caioi sp. nov. is described from Pampa biome in south Brazil. The species of this family are usually large and strong sclerotized mites with robust and spinulose legs I and II. Until now records of species for South America were known only from Chile and Argentina.

The Pampa biome is an extensive natural grasslands region located between northeastern Argentina, Uruguay and south of Brazil (Suertegaray & Silva, 2009).This region includes some very fragile environments and is of common sense that the presence of grasslands and the hindering of forest expansion over the area are nowadays greatly influenced by the human activities.In the other hand this activities has great negative influence on the conservation of the natural areas and the biodiversity of the region (roeSch et al., 2009).The region focused in this paper (Área de Proteção Ambiental -APA -do Ibirapuitã; approximate coordinates 29°57'22" -30°51'55"S, 55°21'02" -55°55'13"W) is a federal protection area which includes private owned land around the almost whole extension of the Ibirapuitã River (icMBio, 2014).
The family was first revised by Franz (1952) and later by coineau (1974) which included an extensive analysis of morphological and also ecological aspects of some species.The last author proposes also the genus Andocaeculus to include "all South American species described by Franz": "Ce genre est destine à recevoir lês espèces que H. Franz a fait connaitre d'Amérique du Sud" (coineau, 1974:279).Based on this comment we suspect that all species described by Franz (1962Franz ( , 1964) ) should be transferred to Andocaeculus.However, this seems to be not accepted once Andocaeculus remains as a monotypic genus including until now only the designed genus type species A. brundini (see taylor et al., 2013:448; checklist of Caeculidae provided by Yves Coineau).The three remaining Microcaeculus species described by Franz (1964) for South America were apparently not examined by coineau (1974) and therefore never formally revised or transferred to Andocaeculus.
All species of the three Caeculidae genera with South American distribution (Andocaeculus Coineau, 1974;Microcaeculus Franz, 1952 andNeocaeculus Coineau, 1967) can be recognized by the tarsal claws of different size on leg I. Andocaeculus, differently from the remaining two genera, can be recognized by the presence of one bothridium on the dorsal side of tarsi I and II as in Caeculus Doufour, 1832Doufour, (see coineau 1974:279):279).Neocaeculus and Microcaeculus should be recognized by differences in the aspidosomal sclerite length, not dorsally overhanging the gnathosoma in the first and overhanging in the second (coineau, 1967; coineau & ennS, 1969; taylor et al., 2013).Regarding biogeographic distribution it's worth to mention that types species and most species of the genera Microcaeculus and Neocaeculus do not have Neotropical distribution being mostly and respectively from Paleartic and Australian regions.
In this paper we describe a new species of Andocaeculus from South America, the first caeculid registered to Brazil.considered: d, dorsal; a, anterior; p, posterior; v, ventral; va, ventro-anterior; vp, ventro-posterior.Only leg articles with spines are indicated.Additional abbreviations used: tr, trochanter; bf, basifemur; fe, femur; ti, tibia; ta, tarsus.

Descriptions
Specimen for transmitted light examination was cleared with Nesbitt's fluid along two weeks and posteriorly washed out with acetic acid over one day and transferred to 80% ethanol; examination on compound microscope was made with the help of a slide containing clove oil.Spines location and counts were accomplished using compound and stereomicroscope for confirmation.Incident light images were taken through a stereomicroscope with attached camera and processed with Helicon Focus 5.3 multi-range program (KozuB et al., 2012).Transmitted light images of cleared female were taken with a compound microscope using a digital camera and also processed with Helicon Focus.Drawings were made using printed images as models and compound microscope and stereomicroscope as three-dimensional shape confirmation tools.Electron scanning microscope (SEM) images were taken using a Jeol-JSM-5200 with attached SLR digital camera.All measurements in text are in millimeters; SEM scale bars are in micrometers.

Andocaeculus caioi
Venter: orange brown tegument suffused with brown areas; epimeres blackish, wrinkled aspect; dark brown genital and anal valves (Fig. 2).Epimeres I not touching the gnathosoma, with a clear seam between them; with three medial positioned and equally spaced small needlelike setae; epimeres I and II apparently fused, with a deep groove between each other; epimeres II also with three medial positioned and close to equally spaced small needlelike setae; epimeres II and III separated by a narrow seam; epimeres III and IV fused, with shallow groove between them, each with four medial positioned small needle-like setae.Genital valves with six pairs of small and thin needlelike setae, genital opening 0.209 long; aggenital sclerite inconspicuous.Anal valve with two pairs of small clavate setae; pseudoanal sclerites with three setae; 0.225 long (Figs 4,6).Remaining ventral agenital seta distribution as in Figs 4, 6.Gnathosoma: naso setae Po and bothridium bo almost of same size and shape, slightly enlarged distally (Fig. 7); subcapitulum dark, almost black, wrinkled aspect, setae absent.Hypostome with two pairs of needle-like setae near base and two distal pairs of very small setae.
Chelicera with one dorso-distal needle-like seta; movable finger terminal, fixed finger regressed and tooth like.Palp (Figs 8, 9) four segmented, with fused femur-genu bearing three dorsal robust needle-like setae, distal one longer as proximal ones; tibia with six robust setae, three dorsal ones and one anterior, all about same length, two smaller retrolateral ones, one dorsal solenidion (Fig. 9); tarsus with two ventral setae, both prolaterally directed, five eupathidia: four distal ones being the two median very close together, the fifth one slightly in retrolateral position (Figs 8,9).
Male.Unknown Variation.Length 1.127-1.594(n=10), width 0.724-1.095(n=10).Natural History.Specimens were collected under exfoliating basalt stones near a small creek (Fig. 41).Further examined material was collected in many other sites in the same area but not necessary close to water bodies (Figs 42).As also noted by otto (1993) we suspect that the species is a specialized Collembola predator as many Entomobryidae were observed under the same rocks where the mites were found; unfortunately we were not able to catch any of them.support.To Antonio D. Brescovit (Instituto Butantan) for providing copies of the extensive Yves Coineau 1974 thesis.To ICMBio crew at Apa do Ibirapuitã, Eridiane Lopes da Silva and Raul Cândido da Trindade Paixão Coelho for help and support.For the Silveira family (Fazenda Rincão dos Moraes) for all the kind reception and logistic support.For Mariano Cordeiro Pairet Jr. and Guilherme Oyarzabal da Silva for the invaluable help on field.
Other examined material.7♀ (MCN ACA 1892-1898) all 31.I.2014, R. Ott, M. Pairet & G. O. Silva leg; all same location as type material.Distribution.Known only for the type locality.Behaviour.Similar as reported by coineau (1974: pl. 3, 17) it was observed on live specimens that mites can present thanatosis behaviour in different positions (spread legs, withdrawn legs or irregular legs position) for many minutes, not moving even if pushed around (Figs 38-40).