A new species of Reticulolaelaps Costa (Mesostigmata: Laelapidae) from the Iberian Peninsula, with a key to world species

A new species, Reticulolaelaps caditanus n. sp., is described based on adult females found in an oothecal cell of Mantis religiosa. The species has several morphological characteristics, including the presence of presternal shields, endopodal III-IV widely connected with sternal shield, 50 pairs of dorsal setae and at least 11 setae x, curly and barbed, and thin and smooth ventral setae including six pairs of setae on the genitoventral shield. A revised diagnosis of the genus with the addition of new characters and a key to the world species of the genus are provided.


Introduction
The genus Reticulolaelaps Costa (species type R. faini Costa) was described by Costa (1968) on the basis of adult males and females from forest litter (Quercus-Styrax) in Israel.
In recent years the genus has gone through new definitions and diagnoses. Nemati et al. (2013) clarified the original diagnosis of this genus and transferred Pseudoparasitus lativentris Karg, 1978 to Reticulolaelaps. Joharchi & Babaeian (2015) refined this diagnosis giving new, albeit incomplete data as to idiosomal poroidotaxy and adenotaxy, and legs characters including leg chaetotaxy; at the same time, P. lativentris was excluded from Reticulolaelaps due to the absence of hypostomal flaps and other gnathosomatic attributes, leg chaetotaxy and male ventral shielding. Recently, Nemati et al., (2019) transferred Laelaspisella elsae Joharchi, Babaeian & Jalalizand, 2016 and P. lativentris to Reticulolaelaps based on precise observations of these two taxa; Pseudoparasitus jilinensis Ma, 2004 was also provisionally transferred to Reticulolaelaps pending a careful study of the type materials. They described new diagnostic characters for R. lativentris, including remnants of membranous hypostomal flaps, gave new information on female characters of R. faini, and provided a new definition and diagnosis of Reticulolaelaps together with a new definition of Pseudoparasitus. Currently, five species complete the list of recognized species of Reticulolaelaps -R. costai Joharchi & Babaeian, 2015, R. elsae (Joharchi et al., 2016), R. faini Costa, 1968, R. hallidayi Joharchi, Nemati &Babaeian, 2013, andR. jilinensis (Ma, 2004).
In this paper, although it was not possible to account for intraspecific variation because of the limited number of specimens available and the single population sampled, the findings presented here may help to clarify the diagnostic attributes of the genus.

Material and methods
Mites were manually removed from the inside of an empty oothecal cell of Mantis religiosa (L.) using a fine brush under a binocular microscope, preserved in 70% alcohol and later cleared in Nesbitt's fluid and mounted in Hoyer's medium. Morphological observations, measurements, and illustrations were made using compound microscopes equipped with differential interference contrast and phase contrast optical systems, drawing tubes and stagecalibrated eyepiece micrometers. Setal notation for the idiosoma follows Lindquist & Evans (1965). Measurements of structures are given in micrometers (µm). Dorsal shield length is midline from anterior margin of vertex to caudal margin. Length of ventral idiosomatic shields are midline, from the anterior margin to posterior edge of each shield. Notation for leg and palpal setation follows Evans (1963,1964). Leg lengths are from the base of the coxa to the apex of the tarsus, excluding the pretarsus. Distinction of pore-like structures on the idiosomatic integument as either poroids (lyrifissures) or glandular openings (solenostomes), as distinguished morphologically by Athias-Henriot (1969) and physiologically by Krantz & Redmond (1987), is presented stylistically in the illustrations. Gland pores are shown in circular form, while poroids are shown in elliptical form following Johnston & Moraza (1991).
The holotype and paratype of the new species are deposited in the Museum of Zoology, University of Navarra, Pamplona, Spain.

Description of the female
Idiosoma 537 long, 439 wide at level of setae J1 (female, holotype).
Idiosomal venter (Figures 2A, B) -Presternal shields present. Sternal shield arch-shaped and fused with endopodal elements between coxae I-II, II-III and III-IV; anterior margin concave and posterior margin strongly concave covered by genitoventral shield anterior margin; sternal shield 58 long medially, 115 wide at level of st2, with sternal setae st1-st3 long (74), smooth and relatively thin, and three pairs of lyrifissures (iv1, iv2, iv3); setae st1 on anterior margin of sternal shield and st3 on endopodal region; transverse intervals st1-st1 65, st2-st2 100 and st3-st3 134; setae st4 absent (Figure 2A, B); large genitoventral shield well ornamented with large cells except on posteromedial region; shield contiguous with exopodal shield posterior to coxae IV; genitoventral anterior margin overlaps more than half the length of the sternal shield (arriving to half the distance between st1 and st2), posterior border contiguous with anal shield; shield 354 long, 334 wide at level of first pair of ventral setae ZV1; genital setae (st5) set at level of coxae IV, similar to sternal setae (83-84 long); genitoventral shield with five pairs of ventral setae (JV1-JV3, ZV1-ZV2), three anterior pairs 83 long and two posterior pairs on posterior border of shield 56 long; shield with one pair of lyrifissures ivo discernible. Anal shield twice as wide as long (112 long 215 wide), with anterior margin straight, posterior margin rounded; well reticulated, and with subequally short, thin circum-anal setae 25 long; gland pores gv3 on Exopodal plates smooth on surface, evenly pointed posteriorly behind coxae IV, continuously fused in a strip alongside coxae II to IV. Peritrematal shields free from exopodals and fused to dorsal shield at level of setae s3; posterior peritrematal shield end contiguous with genitoventral shield at level of setae ZV1 ( Figure 2A); this shield with two pairs of discernible glandular openings (gp2, gp3) and two pairs of lyrifissures (ip2, ip3). Peritremes well developed, extending to level of setae z1. Spermathecal structures unsclerotized, indiscernible.
Male of the species and immature instars are unknown. Etymology -The species name "caditanus" refers to the Spanish province where the new species was found.
Remarks -Differences between this species and other known members of Reticulolaelaps are summarized in the key to the species. The pattern of idiosomal glands and lyrifissures (incompletely illustrated in this work) is similar to the pattern described by Kazemi & Beaulieu (2016) for other members of Laelapidae.

Revised diagnosis of genus Reticulolaelaps
The last review of the genus Reticulolaelaps given by Nemati et al, (2019) can be extended after the description of R. caditanus n. sp.. The well-sclerotised, reticulate, convex holodorsal shield hypertrichious: podonotal region with complete chaetome, may bear extra setae jx; setae j1, z1, together with id1, on the vertical region of shield are different in shape and length from the rest of dorsal setae; setae r6 off shield, on soft lateral cuticle. Dorsal poroidotaxy and adenotaxy as other members of the family ( Figure 1A).
Reticulolaelaps shares several characters with other genera of the family such as Cyclothorax von Frauenfeld, 1868, Gecarcinolaelaps Casanueva, 1993, Iphiolaelaps Womersley, 1956, Iphiopsis Berlese, 1882, Jacobsonia Berlese, 1910, Myrmozercon Berlese, 1903, Narceolaelaps Kethley, 1978, Urozercon Berlese, 1902, and members of the Iphiopsididae Kramer. All these genera are associated with different arthropods. Reticulolaelaps has been found in ant nests, but has never been found on ants themselves. R. caditanus n. sp. has been found in the oothecal cell of a mantid insect sharing habitat with the predatory genus Bdella Latreille, 1795 and oribatids such as Bipassalozetes bidactilus (Coggi, 1900) and Phauloppia pilosa (C.L. Cock, 1841) (Moraza & Sanchez, 2016). However, the association of R. caditanus with the mantid insect has been ruled out since the cell was long empty; the cell may have only served as a safe space to feed and take refuge.
Due to its cheliceral morphology, Joharchi and Babaeian (2015) speculated that Reticulolaelaps prey on small invertebrates in the ant nests. Its gnathosomal structures (internal malae complex, large membranous flaps on the palp-trochanter and gnathotectum with anterior membranous part) could be structural adaptations to help it to obtain food. The flaps overlap the distal ventral region of the gnathosoma and those, together with anterior membranous part of the gnathotectum, which dorsally covers the buccal region, form an enclosed space that may improve control over the prey after tearing into it with its small, yet powerful, chelicerae.
Key to the world species of Reticulolaelaps (females)