First record of a schizomid , Stenochrus portoricensis ( Schizomida : Hubbardiidae ) , in Slovakia

The order Schizomida is a small group of arachnids, currently represented by two recent families: Protoschizomidae Rowland, 1975 with two genera and 12 species; and Hubbardiidae Cook, 1899 with 48 genera and 271 species worldwide (Harvey 2007, Armas 2010, Monjaraz-Ruedas 2012). Schizomids can be found in leaf litter, under rocks, in caves and other subterranean voids, in many tropical and subtropical regions of the world. Some species have been recorded from greenhouses and other artificial environments in Europe, demonstrating their ability to withstand long-distance transport by human commerce (Harvey 2003). Three species have previously been recorded from greenhouses in Europe. Schizomus crassicaudatus (O. P.-Cambridge, 1872) was introduced from Sri-Lanka into France. Zomus bagnallii ( Jackson, 1908) was introduced from Southeast Asia, the Seychelles or Mauritius into Great Britain (Harvey 2003, Blick 2006). Stenochrus portoricensis Chamberlin, 1922 has been introduced into Great Britain, Spain (Canary Islands) and the Czech Republic (Harvey 2003, Blick 2006, Korenko et al. 2009). All of the specimens from Europe were collected from heated greenhouses. Undetermined schizomids have been collected from two greenhouses in Germany (Cokendolpher et al. 2006).

Two juveniles and five females were dissected, studied as permanent slide mounts, and photographed using a Leica DM1000 stereoscopic microscope with an ICC50 Camera Module (LAS EZ application 1.8.0).Other specimens were preserved in 80 % or 96 % ethanol and were photographed using a digital camera CANON EOS 1100D connected to a Zeiss Stemi 2000-C stereomicroscope.The female genitalia were dissected in 96 % ethanol and macerated using NaOH solution, after which they were mounted on a permanent slide in Swan's fluid.Digital images were montaged using the "Combine ZP" image stacking software.The specimens were identified by J. Christophoryová and M. Krumpál.The material is deposited in the collection of the first author in the Comenius University, Bratislava.
At first, only juvenile specimens were collected during our research in the Botanical Garden of the Comenius University.Their identification was difficult because the majority of recent schizomid descriptions are based on the characters of adults.The juveniles were smaller and markedly less sclerotized (Fig. 2B) and were characterized by features typical for the genus (Fig. 4).The identification of the species was equivocal prior to finding the females.

Natural history
Stenochrus portoricensis naturally occurs in Mexico and the Caribbean, but has been introduced to many other countries (e.g. the USA, Rio de Janeiro in Brazil, Colombia, Ecuador, the Canary Islands, Great Britain and the Czech Republic) (Reddell & Cokendolpher 1995, Tourinho & Kury 1999, Harvey 2003, Korenko et al. 2009, Kury et al. 2010).The majority of the males are known from southern Mexico, but some have been found on Caribbean Islands (Tourinho & Kury 1999).The species is fac-ultatively parthenogenetic (Martín & Oromí 1984) and only females and juveniles have been found in heated greenhouses (Cloudsley-Thompson 1949, Korenko et al. 2009).Parthenogenesis in this species probably facilitates its importation.This species has been reported from caves, under rocks, in leaf litter and soil, in both synanthropic and disturbed habitats (Rowland & Reddell 1980, Martín & Oromí 1984, Reddell & Cokendolpher 1995, Tourinho & Kury 1999, Santos et al. 2008, Armas 2010).Some specimens have been collected in association with ants and termites (Martín & Oromí 1984, Reddell & Cokendolpher 1995, Santos et al. 2008).In Tenerife, only females are known from volcanic pit at low altitude (Martín & Oromí 1984, Oromí & Martín 1992).In the Czech Republic, the species was found under pieces of bark lying on wet soil in a greenhouse in the Botanical Garden of Masaryk University, Brno (Korenko et al. 2009).
The records provided in the current study are consistent with known natural history patterns.Stenochrus portoricensis occurs in Slovakia in heated greenhouses, with a temperature of about 26 °C, in the soil and under stones.There have not been importations of plants from tropical areas or other botanical gardens for several years and some insecticides have been regularly applied one to two times per month (Vertimex, Confictor, Omite).According to these facts, the population of S. portoricensis can probably survive in the greenhouses.Only females and juveniles were collected, which implies that the Comenius University population of this species is probably parthenogenetic.

Fig. 1 :
Fig. 1: heated greenhouses in the Botanical Garden of the Comenius University in which Stenochrus portoricensis occurs.A. interior view of greenhouse.B. Detail of the stones under which females were collected.-photos: Jana Christophoryová