Description of a new rake legged mite of the genus Allocaeculus (Acariformes: Caeculidae) from Turkey with description of variation in dorsal setation

A new species Allocaeculus turcicus n. sp. (Acariformes: Caeculidae) is described based on specimens collected from Karanlikdere Valley, Yozgat, Turkey. Some asymmetries and numerical variations of dorsal body setae of the new species are recorded. A list of the species of this genus is provided. In Turkey, this genus is recorded for the first time.

Adults of Caeculidae characteristically bear eight heavily sclerotized dorsal plates. They are commonly referred as rake-legged mites due to the presence of elongate spine like setae on the legs, particularly the first pair. These spines are used in the capture of small arthropods such as collembolans (Otto 1993;Walter et al. 2009;Taylor et al. 2013;Taylor 2014).
In this paper, the species Allocaeculus turcicus n. sp. from Karanlıkdere Valley, Turkey is described. In order to contribute to the knowledge of mites in Turkey, a faunistic study was carried out in Karanlıkdere Valley during 2013-2014. We also intend to demonstrate variation in dorsal setation of the new species. Finally a list of species of this genus and the countries where they have been reported is provided.

MATERIALS AND METHODS
Samples obtained from mosses on the rock in Karanlıkdere Valley, Yozgat were put in plastic bags. Mites were extracted using a Berlese funnel apparatus in the laboratory. They were preserved in 70 % ethanol, cleared in 50 % lactic acid for a few hours and then mounted on microscope slides in modified Hoyer's medium. All measurements were done with ocular micrometer attached to a compound microscope (Olympus CX21) and given in micrometers (µm). Measurements of the holotype are given first; those of paratypes are in brackets. Specimens studied with SEM were cleaned by soaking in Terg-a-zyme solution for 2 h. After airdrying, samples were glued onto aluminium holders and coated with 180 A o of AuPd prior to photography. The terminology used is based on Franz (1952) and Mangová et al. (2014).
Diagnosis -Prodorsal plate covers the rostrum wholly or mostly; two pairs of ocelli present on prosoma; idiosoma long oval or rentangular in shape; legs with tridactylous.
Pedipalps short and thick, 250 in length.
Palptibia three long claws, about 40 in length, Pointed seta s situated anteriorly on palptibia. Palptarsus three short seta o and one pointed seta s. Genu with a long seta r, directed anteriorly. Femur with one clubbed setae q ventrally, 50 in length and three clubbed seta dorsally q 1 -q 3 ( Figure 9F, G).
Leg I with robust 9 spines and 1500 in length. Leg I ending in 2 tarsal claws (cl), 70 in length. Spines t situated anteriorly on tarsus, and 50 in length. Metatarsus bearing 3 spines (c, c, a) anteriorly (190, 190 and 170   Male and immature stages -Unknown.
Etymology -The name of this new species, turcicus, refers to the country in which it was found.
Remarks -To date, this family was recorded in Turkey only once and from a single locality (Karaca et al. 2012). Observations showed that this new species has some asymmetry and numerical variations in dorsal body setae. All these cases are summated in Table 2. In the family Caeculidae, variations have been observed by some authors (Enns 1958;Otto 1993;Taylor et al. 2013). Variation in dorsal setation on Neocaeculus imperfectus Taylor, Gunawardene and Kinnear, 2013 was reported by Taylor et al. (2013). They also stated that those variations in ventral and leg setations are common within this species. Detailed discussion of patterns of variation in setation within and between Ceaculid species was provided by Coineau (1974a). The possible reasons of such variation are unknown and its significance for taxonomy not estimated. There are no organisms without variations. Adaptations to different environmental conditions of organisms lead to variations in genetic and phenetic terms. Organisms adapt to environment conditions such as temperature, humidity, amount of nutrients, pH, sunlight and radiation, which can cause genetic and phenetic differentiation and intraspecific variation.
In the present work we listed the 34 valid species of the genus Allocaeculus and the countries where they have been found (Table 1). Because of absence of specific key for the species of this genus, this check-list will be useful as a first step for the elaboration of such a tool. The first standard key to the species of this genus was developed by Franz (1952) who included 13 species. In the later years (1955) and (1957) he provided the keys for 9 and 10 species respectively, most of them were also included in the previous key. Untill now, no key apart from those has not been elaborated. The recent increase in the number of described species stresses thus the urgency of species key for this genus.