Meristacarus perikopesis, Fernandez, Nestor, Theron, Pieter, Leiva, Sergio & Jordaan, Anine, 2018

Fernandez, Nestor, Theron, Pieter, Leiva, Sergio & Jordaan, Anine, 2018, The family Lohmanniidae (Acari, Oribatida) II: two new Oribatid mites, Meristacarusperikopesis sp. n. from Costa Rica and Torpacaruseidikoterai sp. n. from Kenya, ZooKeys 743, pp. 43-66 : 43-47

Meristacarus perikopesis sp. n. Figures 1-7, 8-10, 11-13, 14-18, 19-22, 23-28

Etymology.

The specific epithet perikopesis is derived from perikopés, (Περικοπές in Greek meaning cuts in English) by the characteristic cross-cut grooves present on the cuticle.

Type material.

Holotype.♀"CR 0978 Tu 15 Costa Rica Turrialba foret naturelle du Catie alt.560 m. Triage d’humus pied arbre à contreforts. 11. IX. 1978. LEG P.WERNER"; material conserved in 70 % ethanol, deposited in MHNG. Paratypes. 2 ♀♀, same data and locality, deposited in MHNG; preserved in 70 % ethanol.

Diagnosis

(adult female). Integument. Very complex with irregular cross-shaped grooves on prodorsum and notogaster. Smooth surfaces: anterior zone prodorsum extending to rostrum; zone posterior to b.sj; subcapitulum; anterolateral zone of prodorsum; epimeral zones; genital plate; preanal plate. Pusticulate surfaces (porose areas) on prodorsum, notogaster. Reticulate–foveate: Sb, S1, S2, S3, S4, S5, S6, S7, S8, S9, S10 transversal bands, notogaster. Colliculate: basal subcapitulum region; areas surrounding 1a epimeral setae; v.sj; anal-adanal zone and BPDA; legs I, II, III, IV. Undulate on lateral epimeral zone. Punctate: entire prodorsum and notogaster. Sulcate: bothridial ring.

Prodorsum. Flat smooth chitinous edge, external to exa, exp, and le setae, postbothridial transverse band sb hardly discernible.

Notogaster. Sixteen pairs of primary notogastral setae: c1, c2, c3, d1, d2, d3, e1, e2, f1, f2, h1, h2, h3, p1, p2, p3;tentransversal bands: S1, S2, S3, S4, S5, S6, S7, S8, S9, S10. Transversal bands S4, S5, S7, S10 not crossing medial notogastral plane; prodorsal, notogastral setae barbate; adoral setae: or1 large, teardrop-shaped; or2 elongate, wide acutely terminating tip; or3 long, thin, sharply tipped.

Description

(Adult female).Measurements 887 (876-920) × 376 (351-386) μm (n: 3).

Shape. Oval (Figure 1).

Colour. Yellow to light reddish yellow; slightly shiny when observed in reflected light.

Cerotegument. Mostly absent, on some regions (e.g., near the bothridium (Figure 6, indicated by solid upwards arrow) observed as very thick smooth layer; on some epimeral zones and legs, gives the impression of randomly distributed dust (Figures 14, 26, indicated by white and black upwards white bar arrow). The cerotegumental layer was most probably degraded during the long period of preservation in alcohol.

Integument. Very complex. Irregular cross-shaped grooves (Figures 1, 3, 4, 5, 6, 13, indicated by solid leftwards arrow) present on entire prodorsum and notogaster, as well as on pusticulate surfaces. Smooth surfaces, anterior zone of prodorsum up to rostrum (Figure 12 indicated by solid rhombus); zone posterior to b.sj (Figure 1 indicated by solid rhombus); subcapitulum (Figures 14, 19, 21 indicated by solid rhombus); anterolateral region of prodorsum (Figure 2 indicated by solid rhombus); epimeral zone (Figure 14 indicated by solid rhombus); genital plate (Figure 15 indicated by solid rhombus); preanal plate (Figure 16 indicated by solid rhombus). Pusticulate surfaces: prodorsum, notogaster, and epimeral region (Figures 1, 8, 9, 10, 12, 13 indicated by white sun with rays) (See Remarks); pustules between 7-20 μm in diameter (Figure 4, pustules indicated by surrounding small squares). Reticulate–foveate on Sb, S1, S2, S3, S4, S5, S6, S7, S8, S9, S10 (Figures 5, 23 indicated by outlined rightwards arrow). This microsculpture is also observed, irregularly distributed, in vicinity of pustules (Figure 4 indicated by outlined rightwards arrow) and cross-shaped grooves (Figure 7 indicated by outlined rightwards arrow). Colliculate: subcapitulum basal zone; surrounding 1a epimeral setae (Figure 18 indicated by diamond shape made up of 4 smaller black diamonds); surrounding vsj (Figure 14 indicated by diamond shape made up of 4 smaller black diamonds); adanal plate and BPDA (Figure 16 indicated by) diamond shape made up of 4 smaller black diamonds; legs I, II, III, IV (Figures 23, 25, 26, 28, indicated by diamond shape made up of 4 smaller black diamonds). Undulate: lateral epimeral zone (Figure 14 indicated by interrupted outlined arrow); punctate on prodorsum and notogaster (Figure 7 indicated by narrow dashed arrow); sulcate: bothridial ring (Figure 6).

Setation (legs not included). Simple, smooth: epimeral (Figures 14, 18); subcapitular a (Figure 20); genital (Figure 15). Simple, barbed: prodorsum (Figures 12, 13), notogaster (Figure 3); subcapitular h, m1, m2 (Figure 19); adanal (Figure 17). Numerous long barbs, principally situated on one side of the seta (Figures 3, 13), sometimes on the opposite side, a few very small barbs can be observed.

Prodorsum. Shape: triangular, rounded apex in dorsal view (Figures 1, 9); triangular in lateral view (Figures 8, 11); in frontal view, triangular with curved sides (Figure 12). Rostrum ovoid (Figures 12, 14); flat smooth chitinous edge present on either side of prodorsal area, externally to exa, exp, and le setae, derived from margin of lateral depression housing legs (Figures 2, 12, indicated by solid upwards arrow); region between level of rosetal insertion and rostrum, smooth, elongate, clearly delimited by flat chitinous edge (Figure 12 indicated by solid rhombus); ro setae large, length 155 (148-171) μm directing forward (Figures 1, 11, 12); le setae directing forward, length 200(196-221) μm (Figure 1, 12); in setae upright, 91 (86-101) μm; exa setae 201(195-228) μm; exp setae 91 (87-98) μm.

Bothridium (bo) ring-shaped, rounded, with particular microsculpture slightly elevated from the cuticular surface (Figures 5, 6), opening directed upwards with slight lateral tilt. Sensillus (Si) pectinate, some pectines elevated but most slanted along main body of Si (Figures 1, 5). Si stem longitudinally sulcate (Figure 6). Postbothridial transverse band sb hardly discernible, situated posterior to bo; in setae situated on sb margin (Figures 1, 5, 11, 12).

Notogaster. Sixteen pairs of primary notogastral setae clearly discernible: c1, c2, c3, d1, d2, d3, e1, e2, f1, f2, h1, h2, h3, p1, p2, p3 (Figures 1, 8, 9, 11). Ten transversal bands: S1, S2, S3, S4, S5, S6, S7, S8, S9, S10 (Figures 1, 5, 8, 9, 11). S1 anterior to setae c1,c2, c3, crossing transverse medial notogastral plane (Figures 1, 8, 9, 11, 12); S2 crossing transverse medial notogastral plane, extending slightly beyond c2 setae, terminating near c3 in a large ovoid tip; S3 situated behind c setal alignment and in front of d setal alignment, crossing medial notogastral plane (Figure 11); S4 behind d1, d2 setal alignment, not crossing medial notogastral plane;S5 oblique, exceeding d1 setal insertion level, terminating in rounded end (Figures 1, 8, 9, 11), not crossing medial notogastral plane; S6 crossing medial notogastral plane, thin band surpassing e2 setal insertion level, laterally extending to unsclerotized lateral longitudinal line; S7at level f1, f2 setal insertion, not crossing medial notogastral plane, terminating near f1 setal insertion; S8 behind f2 setal level, extending obliquely to f1 setal insertion, crossing medial notogastral plane; S9 situated at h setal insertion level, crossing medial notogastral plane; S10 in front of p1 insertion level, not crossing medial notogastral plane.

Five pairs of lyrifissures present: ia, ip, im, ips, ih; ips situated on adanal fold band (BPDA) (Figure 10); im near e2 setae and ih behind p3.

Lateral region. In lateral view certain transverse bands are hardly discernible, principally S8, S9, S10 (Figure 11). Flat smooth prodorsal margin present on either side of cavities housing legs I-IV when retracted. Anterior notogastral zone presenting conspicuous tectum and clearly defined unsclerotized lateral longitudinal line (Figure 8).In posterior notogastral zone, where unsclerotized line is absent, notaspis and pleuraspis not delimited (Figure 8).

Ventral region. Subcapitulum more or less triangular, posterior zone ovoid. Four pairs of subcapitular setae, a, m1, m2, h. Smooth elevated triangular structure (Figure 19 indicated by*) containing m2, m1, a setae determined by oblique line from subcapitular marginal zone to medial longitudinal plane, with h setae situated outside triangle in a depressed area (Figure 19). Cuticle smooth in central zone of this depressed area, but colliculate microsculpture observed bordering the triangular elevated zone (containing m2, m1, h setae). Adoral setae (Figures 19, 20):or1 large, teardrop-shaped; or2 elongate, wide, terminating in acute tip; or3, long and thin, sharply tipped. Coxisternal region divided into two parts by ventrosejugal groove (Figures 14, 21). Apodemes clearly visible; epimeral setal formulae 3-1-3-4 (Figure 10). Genital plate rounded, undivided, usually with ten pairs of setae, but sometimes only nine pairs (Figures 14, 15); six simple setae paraxially and three or four antiaxially. Preanal plate more or less triangular, rounded central zone (Figures 14, 15, 16).

Adanal plate with four pairs of setae (Figure 16); setae with very small barbs (Figure 17). Band BPAD clearly visible; lyrifissure ips present near margin of this band (Figure 10).

Legs. Two types of femora can be distinguished. Femora legs I and II displaying large ventral blade (Figure 14), femora legs III and IV with poorly developed ventral blade. Setae u laterally flattened on all legs (Figures 23, 24, 25, 26, 27), with flap housing s setae on claw (Figure 27 indicated by Solid upwards arrow). Famulus spur-shaped (Figure 28), setal formulae I (0-4-2-2-16-1) (2-1-2); II (0-5-4-4-15-1) (1-1-1); III (2-4-3-4-13-1) (1-1-0); IV (2-3-2-3-13-1(1-0-0).

Remarks.

The porose area indicated by Grandjean 1934: 37 “… et par sesairesporeuses au nombre de plusieurscentaines, répartiessurtoute la surface du corps" describing Meristacarus porcula , is referred to as pusticulate cuticular microsculpture (diameter of pustules between 20-7μm) in this paper. These structures were studied using optical microscopy in order to confirm their similarity to the description given by Alberti et al. 1996: 280 " In lohmanniid mites numerous distinct porose areas may be seen in certain taxa (e.g. Meristacarus , Mixacarus )". In 1997 Alberti et al. 1997: 58-63: indicated: "In light microscopy they appear as distinct patches of higher transparency and show the fine striation perpendicular to the surface, that is typical of porose areas (Fig. 29)" and referred to SEM studies: "This similarity is also evident with SEM (Fig. 30 A) the porose areas are not visible from the exterior but very shallow depressions indicate sometimes their location".

Our results are markedly different to Alberti et al. 1997 (Fig. 30A) as, although the porose areas and/or shallow depressions are not visible under SEM, well-defined pustules are clearly discernible. Also, the irregular cross-shaped grooves differ from those described by Alberti et al. 1996, 1997, where reference was made to pores, for example Alberti et al. 1996: 281, indicates, with reference to function "Such a glandular function is certain in the typical porose areas (octotaxic system, areas of part of the prosoma) in the medio dorsal porose areas of Acrogalumna males and the numerous areas of Mixacarus " and "The latter two types are remarkable in being innervated. The secretions pass through the inner layers of the epicuticle (no open pores) and are presumably lipids" and later: "This statement can now be modified in such a way that organs with one or another functions -respiration on the one hand or secretory on the other hand …”.