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

Uma nova espécie de Andocaeculus (Acari, Caeculidae) do bioma Pampa, sul do Brasil

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

Uma nova espécie de Andocaeculus (Acari, Caeculidae) do bioma Pampa, sul do Brasil

Ana Paula Ott^I; Ricardo Ott^II

^IDepartamento de Fitossanidade, Faculdade de Agronomia, Universidade Federal do Rio Grande do Sul. Av. Bento Gonçalves, 7712, 91540-000, Porto Alegre, RS, Brazil. ([e-mail])

^IIMuseu de Ciências Naturais, Fundação Zoobotânica do Rio Grande do Sul. Rua Dr. Salvador França, 1427, 90690-000, Porto Alegre, RS, Brazil. ([e-mail])

ABSTRACT

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.

Keywords: Mite, Neotropical, South America, taxonomy.

RESUMO

Uma nova espécie de caeculídeo, Andocaeculus caioi sp. nov., é descrita para o bioma Pampa no sul do Brasil. As espécies desta família apresentam o corpo bastante esclerotizado e as pernas I e II com espinhos robustos. Até o momento, registros de espécies desta família na América do Sul eram conhecidos apenas para o Chile e Argentina.

Palavras-chave: Ácaro, neotropical, América do Sul, taxonomia.

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 29º57’22" - 30º51’55"S, 55º21’02" -55º55’13"W) is a federal protection area which includes private owned land around the almost whole extension of the Ibirapuitã River (icMBio, 2014).

Caeculidae are usually large and strong sclerotized mites which prey on Collembola (Otto, 1993). The family is usually linked with arid habitats around the world (taylor et al., 2013). The Caeculidae includes nowadays 97 extant species distributed in seven genera (Taylor et al., 2013). At least five species are known from South America: Andocaeculus brundini (Franz, 1962), Neocaeculus bruchi (Berlese, 1916) and Microcaeculus weyrauchi Franz, 1964 from Argentina; M. castrii Franz, 1964 and M. nudus Franz, 1964 from Chile.

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 recevoirlês 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 (1962, 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 and Neocaeculus 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, 1832 (see Coineau 1974:279). 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.

MATERIAL AND METHODS

Descriptions follows mainly Taylor et al. (2013), modified for the description of legs spines position and Iheringia, Série Zoologia, Porto Alegre, 104(3):355-363, 30 de setembro de 2014 numbers. Six positions for spines and spine rows were 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.

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.

Examined material is deposited at acarological collection of Museu de Ciências Naturais da Fundação Zoobotânica do Rio Grande do Sul (MCN, curator R. Ott).

Andocaeculus caioi sp. nov.

(Figs 1-42)

 

Type material. Holotype ♀ from Fazenda Rincão dos Moraes, Área de Proteção Ambiental do Rio Ibirapuitã, Sant’Ana do Livramento, Rio Grande do Sul, Brazil (30º28’54"S - 55º33’50"W), 29.XI.2013, R. Ott leg. (MCN-ACA 1889). Paratypes: 2 ♀ , same data as holotype (MCN-ACA 1890; MCN-ACA 1891).

Etymology. The noun in apposition is a patronym in honour to Mr. Caio Silveira owner of the Fazenda Rincão dos Moraes and full supporter of the research activities on the Federal Environment Protection Area of the Ibirapuitã River ("APA do Ibirapuitã").

Diagnosis. Andocaeculus caioi sp. nov. can be recognized by the tarsal bothridia on the legs I and II. The species differs from A. brundini by the absence of aspidosomal setae Pp and dorsal setae a1 and b1; can be also recognized by the paired setae b2 and c2 and by two setae at anterior face of trochanter II.

Description. Female (MCN ACA 1891, paratype). Idiossoma length 1.594; width 1.079.

Dorsum: orange brown tegument with dark brown to blackish sclerites (in ethanol; Fig. 1). Aspidosomal sclerite blackish, 0.451 long, 0.386 wide; setae Pa on anterior third of sclerite at the high of the anterior largest sclerite portion, setae Pm and Pp absent (Figs 3, 5). Two pair of eyes on small triangular and blackish sclerite at level of posterior quarter of aspidosomal sclerite (Figs 1, 3, 5). Centrodorsal sclerite dark brown with blackish ridges, 0.467 long, 0.403 wide; paired setae a1, b1, c1 present; setae a1 more than twice apart from each other as for b1 and c1 (Figs 3, 5). Lateral sclerites dark brown with blackish ridges, 0.515 long, 0.129 wide; setae a2, b2, c2 present, all positioned on middle line of sclerite; b2 paired, c2 paired; lyrifissure ia transversal, between a2 and b2, on the ectal border of sclerite; lyrifissure im obliquous between b2 and c2, close to the border of the sclerite (Figs 3, 5). Medial sclerites dark brown with blackish ridges, close to reniform shape, apart from each other around its half width, 0.113 long, 0.274 wide; setae d1, d2 present, ds absent. Posterior sclerites rounded with a mesal somewhat narrowed tip, close together, dark brown with blackish ridges, 0.174 long, 0.258 wide; setae e1, e2 present, es absent; three additional setae present on postero-lateral position of each sclerite (Fig. 5). Pseudoanal sclerite less sclerotized, orange brown, only seta hs present.

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).

Legs: blackish with white to light yellowish setae. Leg setae clavate or needle-like shaped, arranged mainly in five rows, ventral rows bearing mostly needle-like seta; all clavate setae mostly on anterior, dorsal or posterior rows. Legs I and II bearing very long needle-like setae (mainly on anterior and ventral sides of femur, genu and tibia) originating on large tubercles (Figs 10, ¹², ¹³). Leg I with five eupathidia, all restricted to tarsus, being four distal ones at base of claws (two on each side) and one at middle length in retrolateral position (Figs 11, 18-21); one distal solenidion on retrolateral side of tibia (Figs 11, 24, 25), one dorsal short bothridium distally on tarsus (Figs 11, 18); clavate setae distribution: tr, a1-1, d0-1; bf, a1-0-0, d0-0-1, p0-1-0, vp1-1-0; fe, a1-0, d0-1, p1-0, vp1-0; ge, a1-1-0-1, d1-1-1-1, p1-1-1-1; ti, a1-1-1-1, d1-1-1-0, p1-1-1-1; ta, a1-1-1-1, p1-1-0-0; needle-like setae distribution: bf, va1; fe, va1; ge, va1-1-0, v1-0-0, vp1-1-0; ti, va1-1-1, vp1-1-1; ta, va1-1-1-1-1, vp1-1-1-1-1. Leg II with three eupathidia, all restricted to tarsus, being two distal ones (the prolateral one at base of claws and the retrolateral one somewhat appart from claws, ^{Figs 13}, 26, 27) and one at middle length in retrolateral position (^{Figs 13}, 29); one distal solenidion on tibia in retrolateral position (^{Fig. 13}); one dorsal short bothridium on distal position of tarsus (^{Figs 13}, 26-28); clavate setae distribution: tr, a1-1, d0-1, p0-1; bf, a1-0, d0-1, p1-0; fe, a1-1, d0-1, p1-0; ge, a1-1-0-1, d1-1-1-1, p1-1-1-1; ti, a1-1-1-1, d1-1-1-0, p1-1-1-1; ta, a1-1-1-1, p1-1-0-0; needle-like setae distribution: bf, vp1-1; ge, va0-1-1, vp1-0-0; ti, va1-1-1, v1-0-1; vp1-1-1; ta, va1-1-1-1-1, vp1-1-1-1-1. Leg III with one distal solenidion on tibia in retrolateral position (^{Figs 15}, 33, 34); one dorsal long bothridium at three quarters of the length of tarsus (^{Fig. 15}); clavate setae distribution: tr, a1-0, d0-1, p0-1; bf, d0-1, p0-1, va0-1, vp1-1; fe, a1, d1, p1, va1, vp1; ge, a1-1-1-1, d1-1-1-0, p1-1-1-1, va1-1-1-0, vp1-0-0-1; ti, a1-1-1-0-1, d0-0-0-1-0, p1-1-1-1-1; ta, a1-1-1-1, p1-1-1-0; needle-like setae distribution: ti, va1-1-1-1-1, vp1-1-1-1-1; ta, va1-1-1-1-1, vp1-1-1-1-1. Leg IV with one dorsal long bothridium at middle length of tarsus (^{Figs 17}, 36, 37); clavate setae distribution: tr, d1, p1; bf, d0-1, p0-1, va0-1, vp1-1; fe, a1, d1, p1, va1, vp1; ge, a1-1-0-1, d1-1-1-0, p1-1-0-1, va1-0-1-1, vp1-0-1-0; ti, a1-1-0-0-1, d0-0-0-1-0, p1-1-1-0-1; ta, a1-1-1, p1-1-0; needle-like setae distribution: ti, va1-1-1-1-1, vp1-1-1-1-1; ta, va1-1-1-1-1, vp1-1-1-1-1.

 

Male. Unknown

Variation. Length 1.127-1.594 (n=10), width 0.724-1.095 (n=10).

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).

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.

Acknowledgements. To RS Biodiversidade Project for financial 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.

Received 22 April 2014.

Accepted 29 September 2014.

• Coineau, Y. 1967. Contribuition à létude des Caeculidae, Troisième série. Développment postlarvaire de Neocaeculus luxtoni n. gen., n. sp. Acarologia 9(1):55-75.
• ______. 1974. Éléments pour une monographie morphologique, écologique et biologique des Caeculidae (Acariens). Mémoires du Museum National dHistoire Naturelle, Série A, Zoologie 81:1-299.
• Coineau, Y. & Enns, W. R. 1969. Contribuition a létude des Caeculidae. 8e série. Deux nouvelles espèces dAustralie: Neocaeculus knoepffleri n. sp.; N. bornemisszai n. sp. Acarologia 11(4):207-221.
• Franz, H. 1952. Revision der Caeculidae Berlese 1883. Bonner Zoologische Beriträge 3:91-124.
• ______. 1962. Ein neuer Microcaeculus aus Südamerika (Acari: Trombidiformes). Verhandlungen der zoologisch-botanischen Gesellschaft in Wien 101-102:98-100.
• ______. 1964. Neue Caeculiden aus Afrika und Südamerika. Verhandlungen der zoologisch-botanischen Gesellschaft in Wien 103-104:82-93.
• ICMBio, 2014. Apa de Ibirapuitã. Avaliable at: <http://www.icmbio.gov.br/portal/biodiversidade/unidades-de-conservacao/biomas-brasileiros/pampa/unidades-de-conservacao-pampa/2233-apa-de-ibirapuita.html>. Accessed on: 20 April 2014.
• Köppen, W. 1948. Climatologia Cidade do México, Fondo de Cultura. p. 152-192.
• Kozub, D.; Khmelik, K.; Shapoval, J.; Chentsüv, V.; Litovschenko, B. & Starikh, V. 2012. Helicon Focus 5.3 Helicon Focus Ltda. Available at: <http://cybercom.net/~dcoffin/dcraw/>. Accessed on: 23 May 2013.
• Otto, J. C. 1993. A new species of Microcaeculus from Australia (Acarina: Caeculidae), with notes on its biology and behaviour. International Journal of Acarology 19(1):3-13.
• Roesch, L. F. W.; Vieira, F. C. B.; Pereira, V. A.; Schünemann, A. I.; Teixeira, I. F.; Senna, A. J. T. & Stefenon, V. M. 2009. The Brazilian Pampa: A Fragile Biome. Diversity 1:182-189.
• Suertegaray, D. M. A. & Silva, L. A. P. 2009. Tchê Pampa: histórias da natureza gaúcha. In: Pillar, V. P.; Müller, S. C.; Castilhos, Z. M. S. & Jacques, A. V. A. eds. Campos Sulinos: conservação e uso sustentável da biodiversidade Brasília, Ministério do Meio Ambiente. p. 42-62.
• Taylor, C. K.; Gunawardene, N. R. & Kinnear, A. 2013. A new species of Neocaeculus (Acari: Prostigmata: Caeculidae) from Barrow Island, Western Australia, with a checklist of world Caeculidae. Acarologia 53(4):439-452.

Publication Dates

• Publication in this collection
  13 Nov 2014
• Date of issue
  Sept 2014

History

• Received
  22 Apr 2014
• Accepted
  29 Sept 2014