Two new species of Bryobia (Acarina, Prostigmata, Tetranychidae) from South France

Abstract Two new species of Tetranychidae belonging to the genus Bryobia are reported from France. Bryobia belliloci sp. n. and Bryobia gigas sp. n. collected on Genista cinerea and Bituminaria bituminosa, respectively, are described and illustrated in the present work. Additional data to the original description of Bryobia cinereae are given and an identification key to known Bryobia species from France is also provided.


Introduction
Among forty eight species of Tetranychidae recorded from France fourteen species belong to the genus Bryobia Koch, 1836, six of them being endemic to this country Dorkeld 2006-2014). Recent sampling efforts conducted near the Mediterranean coast disclosed two new species of tetranychid mites belonging to this genus. In the current paper we report their descriptions, we complete the description of B. cinereae with measures and drawings of characters usually not reported in descriptions and we provide a key to the fourteen species of Bryobia known from France.

Material and methods
Mites were collected directly from field samples in 70% ethyl alcohol. Following clearing in lactic acid (50%) for 24 hours they were mounted in Hoyer's medium. The specimens were examined using a Leica DM LB 2 phase contrast microscope and illustrated with the aid of a drawing tube attachment (camera lucida). Measurements were taken using the imaging software Perfect Image® (Clara Vision) coupled with ProgRes® Capture Pro 2.6 software for image acquisition. The setal nomenclature used in the descriptions follows Lindquist (1985). Leg setal counts are given in the order: coxatrochanter-femur-genu-tibia-tarsus. Numbers of setae refer to tactile setae, solenidia are given in parentheses and alternative counts are given in brackets. All measurements are given in micrometers and correspond to the holotype followed (in parentheses) by minimum and maximum values from paratypes. Setae were measured from the centre of their setal bases to their tips. The distance between two setae was measured as the distance from the centre of one setal base to the other. Diagnosis. Limited anterior dorsal propodosomal projections over gnathosoma, outer prodorsal lobes scarcely developed more resembling to tubercle-like structures, inner lobes more developed, base almost fully fused, more or less cone-shaped, with wide shallow incision between inner vertical setae (v 1 ). Dorsal setae elongate, serrate, with sharp tips, inserted on tubercles, subequal in length on hysterosoma, second pair of dorsocentral hysterosomal setae (d 1 ) longer than distance to consecutive setae (e 1 ) insertions, f 1 and f 2 setae marginal and contiguous. Empodia with two rows of tenent hairs.
Dorsum. Prodorsal lobes similar in shape to females (Fig. 5A), prodorsal setae v 1 and v 2 elongated and serrate, v 2 the largest about 3 times the length of v 1 ; an imaginary transverse line joining the tips of v 2 setae passes well the tips of v 1 . Dorsal body setae slender, needle-like and serrate, inserted on tubercles. Setae c 1 and e 1 shorter than distances between consecutive setae, d 1 longer than distance between setal insertions d 1 and Legs. Shorter than body length, leg I 233 long (including coxa). Internal lateral seta (l') on femur I large. Leg setal counts as follows: True claws uncinate with one pair of tenent hairs, empodia with two rows of tenent hairs. Tarsus III with solenidion well-separated from tactile, proximal.
Legs. Shorter than body length, leg I 196 long (including coxa). Internal dorsal row on femur I with one long seta finely serrate. Leg setal counts as follows: True claws uncinate with one pair of tenent hairs, empodia with two rows of tenent hairs.
Remarks. The combination of prodorsal lobes poorly developed, dorsal setae not spatulate but slender and leg setal counts brings this species very close to B. cinereae Auger & Migeon, 2014. It can be distinguished from this species by the shape and the size of dorsohysterosomal setae: they are wider, stouter in B. cinereae but longer in B. belliloci. Thus, dorsocentral setae are shorter than the distance between consecutive setae in B. cinereae whereas d 1 setae surpass well e 1 setal insertions in B. belliloci. Notice-able differences are also present regarding the following morphological characters in B. belliloci: 1) the incision between the inner prodorsal lobes is wider and shallower; 2) the four legs are longer; 3) the peritremal distal enlargement is shorter; 4) the internal lateral seta l' 1 on femur I is longer (Table 1); 5) coxisternal setae 1b and 1c are similar in length compared to those of B. cinereae (Table 1) but the coxisternal seta 1b is serrate, quite stout, versus weakly serrate and narrower in B. cinereae. (Fig. 3D, E).
Etymology. The species designation belliloci refers to a village that felt into ruin, named Bell Lloc (meaning beautiful place in Catalan language) that is close to the place where mites were collected. Remarks. Additional data to the original description of B. cinereae are provided. Despite that usually not included in descriptions, they appeared to be useful for the comparison of this species with B. belliloci. Drawings of the two coxisternal setae 1b and 1c are shown in Fig. 3E. Measures of their lengths and that of the internal lateral seta l' 1 present on femur I in holotype and paratypes are given in Table 1.    between the inner lobes to their tip, excluding setae). Incision between median and outer lobes deep and narrow. The imaginary transverse line passing to the top of the outer lobes crosses inner near or just above the bottom of the incision. The line joining tips of second pair of propodosomal stae (v 2 ) located on the outer lobes generally passes just above the bases of the first pair (v 1 ). Distance between v 1 and v 2 setae insertions 29 (19-29) and 86 (86-103), respectively, v 1 and v 2 setae subequal in length, v 1 and v 2 subspatulate to spatulate, v 2 wider. Dorsal body setae spatulate, palmate, rough, serrate, inserted on small bulge-like structures, subequal in length, sc 1 the shortest (   . Sacral setae (f 1 and f 2 ) in marginal position, not contiguous. Dorsal integument on propodosoma with irregularly rounded reticulated granulated pattern medially more elongated laterally and oblique. Folds on hysterosoma mostly transverse, irregularly arched in the caudal part. Two pairs of more or less oval-shaped shallow dimples present between d 1 -d 3 , and e 1 -e 3 setae and one present posteriorly. Gnathosoma. Stylophore longer than wide. Tibial claw of palpus bidentate. Palptarsus subequal in length to tibial claw, about 28 (27-29) long with three tactile setae, three eupathidia and one solenidion (Fig. 7D). Eupathidia ul'ζ, ul''ζ shorter than solenidion, suζ longer than solenidion. Peritreme anastomosed distally in a relatively long and slender enlargement, 62 (52-71) long (Fig. 7E).
True claws uncinate with one pair of tenent hairs, empodia with two rows of tenent hairs. On femur I, internal seta smooth, dorsal seta serrate.
Remarks. Bryobia gigas is morphologically close to three species, that belong to a species-group characterized by: 1) prodorsal inner and outer lobes very well developed, outer teat like not triangular, anteromedian well separated; 2) associated setae forming a duplex on tarsus IV, tactile member shorter than solenidion; 3) similar setal counts especially on leg I with 29 and 16 setae on tarsus and tibia, respectively, and on leg II with 19 and 9 setae on tarsus and tibia, respectively; 4) a pair of tenent hairs on the empodium of the foreleg and two rows of tenent hairs on the other empodia. These species are Bryobia osterloffi Reck, 1947, B. vasiljevi Reck, 1953and B. lagodechiana Reck, 1953 Among this species-group B. gigas and B. lagodechiana have a similar large body size. Bryobia gigas is mainly distinctive from B. lagodechiana by the shape of the inner incision between the anteromedian prodorsal lobes which is wide and bottom rounded in the former whereas narrow in the latter. In addition, the line that passes to the tips of v 2 setae does not reach the bases of v 1 setae in B. lagodechiana. They also have a different setal count on genu I with 7-8 and 4-5 setae present in B. gigas and B. lagodechiana, respectively.
Bryobia gigas can be easily distinguished from B. osterloffi and B. vasiljevi by its body and leg sizes which are far smaller in the latters. Moreover, in B. osterloffi, the incision between the inner prodorsal lobes is wide but less deep than in B. gigas (the line that passes to the top of the outer lobes does not reach the bottom of the incision between inner lobes), it is not bottom-rounded but with a flat bottom and the distal part of the peritreme is less elongated. Bryobia gigas also differs from B. vasiljevi by the incision between the inner prodorsal lobes which is narrow. According to Livshits and Mitrofanov (1971), 6 setae are present on the femora III and IV of B. vasiljevi whereas 5 are present in B. gigas. However, type's examination of B. vasiljevi in Reck's collection gave conflicting data because 5 setae only are present on femora III and IV of the 21 type specimens. As a consequence, this morphological criterion cannot be used to distinguish between the two species.
Etymology. The specific epithet gigas, name given to "Giants" in Greek mythology, refers to the quite unusual large body and legs sizes of this species.