Ololaelaps formidabilis Berlese, 1913

Beaulieu, Frederic, Quintero-Gutierrez, Edwin Javier, Sandmann, Dorothee, Klarner, Bernhard, Widyastuti, Rahayu, Combita-Heredia, Orlando & Scheu, Stefan, 2019, Review of the mite genus Ololaelaps (Acari, Laelapidae) and redescription of O. formidabilis Berlese, ZooKeys 853, pp. 1-36 : 1

Ololaelaps formidabilis Berlese, 1913 Figs 1, 2, 3, 4, 5, 6, 7, 8

Diagnosis.

Dorsal shield broad, length/width ratio ~1.3-1.4, lightly reticulate, bearing 39 pairs of simple setae, including px2-3, plus one unpaired seta Jx (sometimes absent); all setae short (21-27; j1, z1, J5 shorter); shield with gland opening gd4 conspicuous, on shield margin; epipleura narrow, strongly reticulate. Female sternal shield as long as wide (length/width ratio 0.96-1.02), bearing setae st1-st3; seta st4 and poroid iv3 on soft cuticle. Hologastric shield with two inverted V-like ridges, and strongly reticulate; cells scale-like in region anterior to anus, bearing seta st5 and five pairs of preanal setae. Soft opisthogastric cuticle laterad of shield with nine pairs of setae. Peritrematal shield free posteriorly, reaching level of coxa IV posterior margin. Metapodal shield suboval, narrowly fused to parapodal shield (and contiguous with hologastric shield) in female. Deutosternal groove with 3-5 denticles per row. Spermatodactyl prominent, 1.8 × as long as movable digit.

Female

(Figs 1-5) (n = 3). Description. Idiosomal dorsum (Figs 1, 2, 3B). Dorsal shield 567-607 long, 410-440 wide (near level of seta S1), covering all dorsal idiosoma, oval-shaped, dome-like, strongly sclerotized and slightly covering ventrolateral margins (epipleura), with a light reticulation on most areas of shield, more conspicuous in opisthonotal region (as shown in region of J3 vs region between j5 and z6) and epipleura strongly reticulate; region anterior to setae j2-s1 with conspicuous, transverse lineae; shield with a delineated marginal strip along its edge (Figs 2, 3A). Shield with 39 pairs of simple setae: j1-j6, z1-z6, s1-s6, r2-r5 on podonotal region, J1-J5, Z1-Z5, S1-S5, px2-3 on opisthonotal region, and usually one unpaired seta Jx (absent in one of three females) inserted on right side (one female) or left side (another female) of shield’s median axis. All dorsal setae slender, relatively short (21-27), with j1, z1 and Z5 shorter (11-15); distance between J5 setae 62-66, distance between Z5 setae 40-46. Dorsal shield with 21 pairs of pore-like structures, including five pairs of gland openings (gd1, gd2, gd4, gd6, gd9) and 16 pairs of poroids; gd4 large, on lateral shield margin (discernible ventrally), posterolaterad of s6 (and level with mid-coxa IV), surrounded by a curved linea (Figs 2, 3A).

Idiosomal venter (Figs 2; 3A, C–E). Tritosternum with columnar base and a pair of pilose laciniae. Presternal area with a pair of well-sclerotized presternal platelets, wedge-shaped, with transverse lineae; region anteromesal to platelets poorly sclerotized, lineate and granulate. Sternal shield 118-125 long, 122-125 wide (at level of setae st2), strongly reticulate, smooth in posterior fifth where overlapped by hologastric shield, with inconspicuous punctae; anterior shield margin straight and posterior shield margin slightly concave, bearing three pairs of simple, slender setae, st1-3 (44-65), and slit-like poroids iv1-2; st1-st1 distance 65-70, and st1-st3 distance 93-98; st4 (45-48) and iv3 on soft cuticle (which may overlap endopodal plate), near posterolateral margin of sternal shield, mesal to coxa III. Endopodal shield besides coxa III–IV large, free, narrowly abutting sternal shield, slightly overlapped by hologastric and exopodal shields. Exopodal shield surrounding acetabula II–IV narrowly fused with sternal shield (via endopodal element) anteriorly between coxae I–II, posteriorly fused with well-developed parapodal element. Peritrematal shield fused anteriorly to dorsal shield at level between coxae I–II, posteriorly free, not extending beyond posterior margin of coxa IV, bearing three pairs of poroids (id3, id7, ip) and two pairs of gland pores (gd3, gdp); peritreme extending anteriorly beyond coxa I, near level of seta z1. Hologastric shield strongly reticulate, 359-366 long, 289-301 wide; one or two discernible inverted-V ridges in anterior half of shield (the anterior ridge may be less evident in some individuals); cells more compressed, scale-like (and narrow, transversally elongate) in region directly anterior to anal opening; shield with inconspicuous punctae; bearing six pairs of slender setae, st5, JV1-3, ZV1-2 of subequal length (37-53), three pairs of poroids, including paragenital poroids iv5; st5-st5 distance 130-138; insertion of paranal setae (24-30) aligned with anterior margin of anal opening, postanal seta shorter (12-19); gland opening gv3 on posterolateral shield margins, at level slightly anterior to paranals; cribrum with 2-3 rows of spicules. Soft opisthogastric cuticle with nine pairs of setae, r6, R1-2 (15-22), R3, ZV3-5, JV4-5 (19-35), four poroids, including one (ivo) at posterior edge of metapodal platelet, and another (idR3; = Rp) near seta R3. Metapodal element oval-shaped, narrowly fused to parapodal-exopodal shield (Fig. 3A, C–E) and contiguous with hologastric shield (may also appear narrowly, inconspicuously fused to hologastric shield in some individuals).

Gnathosoma (Fig. 4). Subcapitulum (Fig. 4A): corniculi horn-like (45-51); internal malae with two pairs of long projections, slightly longer than corniculi, median pair fringed at its base; labrum acuminate, slightly longer than internal malae; hypostomal and capitular setae smooth, h1, h3, pc (27-44), h2 shorter (20-24); deutosternal groove with five (1 female) or six rows (2 females) of denticles, progressively broader from posterior to anterior, each with 3-5 denticles. Cheliceral (Fig. 4B) fixed digit (63-68) with a subapical, offset tooth, followed by two moderately large teeth and setiform pilus dentilis, movable digit with two similarly sized teeth; simple dorsal seta. Gnathotectum (Fig. 4C) with anterior margin subtriangular, irregularly and lightly serrate. Palp (Fig. 4D) with normal chaetotaxy for Laelapidae (sensu Evans and Till 1965), with 2-5-6-14-15 setae on trochanter-femur-genu-tibia-tarsus; palptrochanter setae v1 and v2 thickened; palpfemur al thickened, blunt apically, palpgenu al1, al2 thickened, spatulate (flat and rounded) apically; palp-tarsal claw with three tines, third (proximal) one smaller.

Legs (Fig. 5). Chaetotaxy normal for Laelapidae (sensu Evans and Till 1966). Leg II slightly thicker than other legs. Lengths of legs: I 471-485, II 360-381, III 342-360, IV 470-485. All legs with ambulacral stalk, claws and pulvillus; entire ambulacrum I (26-28), including claw I (8-10), slightly shorter than ambulacra II–IV (31-39) and claws II–IV (12-15), respectively. Most setae slender and of moderate length, except a few shorter and/or thickened setae: femur II with al2 short; femur III–IV with pd and pl 2-3 times shorter than v1 and al; tarsi II–IV with av1-2, pv1-2, mv, md thickened, and md, al1-2, pl1-2 slightly thickened, pl2 thickened on tarsus IV.

Spermatheca. Not discerned.

Male

(Figs 6-7) (n = 1) Description. Idiosomal dorsum. Dorsal shield 493 long, 382 wide (at level of setae S1), as female: covering all dorsal idiosoma, oval-shaped, dome-like and slightly covering ventral surface. Poroidotaxy, adenotaxy, chaetotaxy and ornamentation essentially identical to those of female; setae slightly shorter.

Idiosomal venter (Fig. 6). Similar to female except the following: holoventral shield 380 long, 106 wide at level of st2, 267 wide at level of ZV1, strongly reticulate; shield bearing 10 pairs of simple, slender setae (st1-5, JV1-3, ZV1-2) in addition to circumanal setae. Exopodal shield fused with holoventral shield posteriorly to coxa IV, and extending anteriorly to level of mid-coxa I. Metapodal element (sigillum) incorporated into holoventral shield (see arrows, Figs 6, 7C).

Gnathosoma (Fig. 7). As female, except: subcapitulum (Fig. 7B): internal malae without the pair of lateral projections, and median projections more fimbriate than in female; deutosternal rows each with 3-5 denticles. Cheliceral (Fig. 7A) fixed digit with one tooth; movable digit with one tooth, subapically bearing an elongate spermatodactyl (102), broadly curved, slightly bent apically, with straight (i.e., not sinuous) duct.

Legs.Chaetotaxy and setae thickness similar to that of female. Lengths of legs: I 406-415, II 301-310, III 295-305, IV 380-395.

Material and depository.

INDONESIA, Sumatra • 1♀, Harapan rainforest, litter from rubber tree plantation, research site HR4b, 01°48'18"S, 103°15'52"E, 71 m a.s.l. (LIPI; internal project ID macrolitterHR4b13_MESOS1_1) • 1♀, same data as preceding (CNC1098357; internal project ID macrolitterHR4b13_MESOS1_2) • 1♀ (with an egg), Bukit Duabelas rainforest, litter in rubber tree plantation, research site BR4b, 02°04'36"S, 102°46'22"E, 51 m a.s.l. (SMNG-ARA-13/59952; internal project ID macrolitterBR4b13_MESOS1_1) • 1♂, same data as preceding (LIPI; internal project ID macrolitterBR4b13_MESOS1_2). All specimens collected on 15.11.2013 by B. Klarner. Additional photos of the species are digitally deposited at ecotaxonomy.org.

Remarks.

Our discovery of Ololaelaps formidabilis in Sumatra appears to be the second record of the species in Indonesia, the first corresponding to the original description by Berlese from Java specimens. It is unique among described species of Ololaelaps in having its metapodal platelet fused to the parapodal plate and free from the peritrematal and hologastric shields. Note, however, that the metapodal platelet is tightly contiguous with the hologastric shield and that in some specimens, at some focal depth, it may even appear narrowly fused with it (Fig. 3A). The metapodal and parapodal plates are fused by a short to elongate connecting ‘bridge’ (Fig. 3A, C–E). Photos shared by Roberto Nannelli, who examined types at the Berlese Collection in Firenze, confirm that at least one female paratype of O. formidabilis has such attribute, although the connecting bridge between the metapodal and the parapodal plates seem slightly broader (Fig. 8B; although not perfectly clear) than for the three females from Sumatra (Fig. 3A, C–E). Berlese’s (1913) original description (fig. 51, plate V) shows a fusion ( ‘bridge’) that is as broad as the width of the metapodal platelet. We consider that the difference between the paratype and our specimen represents intraspecific variation. In addition, O. formidabilis has two inverted-V-shaped ridges on the anterior half of its hologastric shield (see arrows, Fig. 1). The posteriormost ridge, shaped more narrowly, is more conspicuous than the anterior one (which is almost U-shaped). The female paratype photographed shows similar ridges (Fig. 8B). Although at least two undescribed species have similar inverted V or U ridges, the shapes of the ridges in these species are distinct from those of O. formidabilis .

The male holotype of O. formidabilis ( Castagnoli and Pegazzano 1985: 151) is also similar to that of the new material, including for its spermatodactyl, which has a similar thickness and length (see arrow, Fig. 8A).

Ryke (1962) redescribed O. formidabilis , via a species key and a single illustration, of the idiosomal venter, which clearly represents another species, distinct from O. formidabilis described by Berlese (1913) and examined by us. The most distinctive character in Ryke’s illustration (his fig. 6) is the metapodal platelet, broadly protruding from its fusion with the hologastric shield, but free from the parapodal shield, in contrast to O. formidabilis sensu stricto. Such partial fusion of the metapodal-hologastric shield is similar to nine other species in the genus ( O. caucasicus , etc., Table 2). Other information included in the key of Ryke (1962), such as idiosomal dimensions and geographic origin (Java), corresponds to those of O. formidabilis , but were probably simply taken from Berlese’s publication (except that Ryke indicated "length 550 μ” instead of 540 μ as written in Berlese (1913)). In the introduction, Ryke (1962) thanked G.O. Evans for "putting [ …] the figures of the type specimens in the Berlese Collection at his disposal". From this, we could interpret that during a visit of the Berlese Collection in Firenze, Italy, Evans examined types and illustrated them, and later on, lent these illustrations to Ryke. We attempted to retrieve putative illustrations by Evans, or Ryke, but without success. It is possible that a mistake occurred at some point and that Ryke’s (1962) illustration is that of a type or voucher specimen representing another species. At present, diagnostic characters included in Ryke (1962) are too limited to determine the correct name of that species (if it has one). Re-examination of Ololaelaps specimens in the Berlese Collection might help resolve this.