Bulbolaelaps neomidae Mašán 2025, sp. nov.
Creators: name: Mašán, Peter
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Mesostigmata
Digamasellidae
Bulbolaelaps
Bulbolaelaps neomidae

description: Bulbolaelaps neomidae sp. nov.
(Figs 2–13)
Diagnosis
Idiosoma suboval to broadly oval, soft integument clearly striated. Dorsal setae mostly long, rod-shaped, sparsely barbed, apically claviform and relatively long; setae s1, r2 (in females) and j1 and r3 (in deutonymphs) outside podonotal shield, on soft integument. Ventral setae mostly smooth and needle-like; Jv5, Zv3 and pa similar to setae on dorsal surface. Shield surface mostly with reticulate to reticulate-punctate pattern in adults or strong punctation (dorsal shields) or specific longitudinal rugosity (sternal shield) in deutonymphs, genital shield smooth. Sternal shield of female subrectangular, without endopodal lateral parts; sternal setae st1–st4 thin and distally attenuated, st3 with adjacent bases and st4 on soft integument. Ventrianal shield with four pairs of opisthogastric setae (Jv1–Jv3, Zv2), relatively narrow and slightly progressively narrowed posteriorly. Peritremes of adults short, reaching level between setae r2 and r3. Deutosternum with five rows of denticles, of which four anterior rows unidentate; distal margin of subtriangular epistome densely fimbriated. Movable cheliceral digit with strong terminal hook and three teeth in females and deutonymphs; fixed digit shortened, shorter than movable digit; male spermatodactyl robust, horn-like, moderately curved and shorter than movable digit. Genu IV and tibia IV without elongate dorsal setae. Male legs II spurred, as in Fig. 10D.
Description
Female (Figs 2A, 3–6, 7B–D, 8A, 8C, 9A, 9B, 10C, 13B). Dorsal idiosoma (Figs 2A, 3). Idiosoma weakly sclerotized, 725–980 μm long, 500–675 μm wide (n = 10), dorso-ventrally flattened, elongate, suboval, covered by two dorsal shields except for the narrow lateral and posterior parts. Podonotal shield (Figs 4A, 4C) 330–390 μm long, 400–500 μm wide, subpentagonal, not capturing insertions of all podonotal setae, with four medial scleronodules at level of s5; anterolateral margins free of anterior parts of peritrematal shields, with anterior margin usually straight between setae z1 and short lateral notches between z1 and j2; lateral margins convex and posterior margin straight or very slightly convex; faintly indicated reticulation on surface near margins and very fine punctation and rugosity on medial and posteromedial surfaces. Arrangement of 22 pairs of anterodorsal setae as follows: j1–j6, z1–z6, s2–s6, r4 and r5 on podonotal shield (of which j1, z1, s2, s3, s6, r4 and r5 on or near lateral margins of shield); r3 on extreme margins of peritrematal shields; s1 and r2 on soft integument; all these setae rod-shaped, sparsely barbed, apically claviform and relatively long (Fig. 4D); setae with medial placement shorter than those on lateral margins of the podonotal shield. Opisthonotal shield 390–450 μm long, 430–520 μm wide, bowl-shaped, widest at the level between R1 and R2, with straight anterior and convex lateral margins and well-rounded posterior margin, sometimes slightly concave between setae Z5; the shield with faint reticulate and punctate pattern in anterior and medial parts, fine rugosity approximately between setae J1–J4 and J1‘–J4‘, and smooth in its posteriormost part; J5 and Z4 are distinctly shorter and S5 distinctly longer than the other setae on the opisthonotum; 20 pairs of opisthonotal setae similar to those on podonotum (except for smooth, whip-like and pointed S5), of which only R1 is located on the soft integument outside shield. Lengths of selected dorsal setae as follows: j1 33–44 μm, j2 60–68 μm, j3 65–82 μm, j4 and j5 50–63 μm, j6 60–72 μm, z1 44–55 μm, z2 85–98 μm, z5 54–66 μm, s3, r4 and r5 85–110 μm, s6 110–137 μm, r3 106–125 μm, J1 62–93 μm, J2–J4 72–100 μm, J5 37–54 μm, Z1 and Z2 84–105 μm, Z4 38–58 μm, Z5 90–135 μm, S2 and S3 92–110 μm, S4 72–85 μm, S5 295–353 μm, R1–R5 86–115 μm.
Ventral idiosoma (Figs 5, 6A, 6B). Tritosternum with narrow base and two barbed laciniae. Presternal plates transversely striate and separately connected to anterolateral margins of sternal shield. Sternal shield subrectangular, 142–166 μm long, 108–129 μm wide, widest at level of iv2, with more indicated fine reticulation on medial surface than in its posterior part; lateral margins straight and without endopodal components between coxae II and III, posterior margin straight to slightly convex; surface with three pairs of setae (st1–st3) and three pairs of slit-like lyrifissures (iv1–iv3), of which two posterior pairs usually located on outer or inner margin of shield; setae st4 inserted in soft integument near posterolateral corners of shield, similar in length and thickness to those on sternal shield. Poststernal area usually with two crescent-shaped sclerites. Epigynal shield elongate, 200–240 μm long, narrowest in anterior part at level of well-developed medial constriction between coxae IV (89–113 μm), widest in posterior part at level of posterolateral corners (163–206 μm), with smooth surface and a pair of setae on posterolateral margins; anterior hyaline part short, not reaching sternal shield, with slightly convex margin (Fig. 7C); posterior margin usually slightly concave; genital lyrifissures (iv5) located on soft integument near posterolateral corners of shield. Postgenital area with four very narrow and transverse sclerites. Ventrianal shield elongate, 255– 325 μm long, 150–190 μm at the widest anterior part, becoming slightly narrower towards posterior margin, slightly concave anteriorly and well rounded posteriorly, with four pairs of opisthogastric setae (Jv1–Jv3, Zv2) in addition to three circumanal setae; circumanal area with weakly indicated reticulation, other parts mostly smooth or with fine transverse lines; adanal setae about 1.5 as long as somewhat thickened postanal seta (ad 69–82 μm, pa 44–58 μm); cribrum well developed, usually with four rows of denticles. Peritrematal shields narrow and reticulate; anterior ends not fused with podonotal shield, free or connected by weakly sclerotized and reticulate scutal element in region of idiosomal apex (Figs 4A, 4C); poststigmatic parts tapered posteriorly and fused with parapodal platelets posterior to coxae IV; peritremes thin, shortened, with anterior tips between setae r2 and r3 (Fig. 4C). Endopodal platelets II–III and III–IV absent or rudimentary. Exopodal platelets between legs I–IV fused into a narrow strips, each of them free from peritrematal shield. A pair of long and narrow metapodal plates present, 75–98 μm long, as in Figs 5 and 6C–E. Soft integument conspicuously and densely striate, with three pairs of setae (Jv5, Zv1, Zv3) in opisthogastric region. Most ventrally located setae needle-like, thin and usually with well-attenuated apical part; Jv5 rod-like, barbed and with well-developed claviform tip, Zv3 and barbed postanal seta needle-like, both with small claviform tip. Lengths of sternal and opisthogastric setae as follows: st1 35–46 μm, st2 and st3 42–53 μm, st4 47–59 μm, st5 39–49 μm, Jv1–Jv3, Zv1 and Zv2 36–53 μm, Zv3 90–105 μm, Jv5 110–135 μm.
Sperm induction structures (Fig. 7D). Insufficiently sclerotized to be satisfactorily identified and observed in all specimens. This system probably relates to the spherical structures on the inner margins of coxae IV, as suspected in members of the related genus Insectolaelaps (Figs 21C, 31C).
Gnathosoma (Figs 8A, 8C, 9A, 9B, 13B). Gnathosoma relatively small compared to size of idiosoma. Corniculi weakly sclerotized, relatively small, apically forked, convergent to each other and enclosed in hyaline membranous sheath, as in male in Fig. 4B. Deutosternal furrow conspicuously narrowed over entire length, with four rows, each bearing only one denticle; fifth row distinctly widened beyond lateral margins of deutosternal furrow, almost semicircular, multidenticulate and interrupted medially by furrow; subcapitulum with three pairs of short transverse lines between rostral setae h3 and pc (Figs 8A, 8C); internal malae apically pointed, with fimbriated outer margins and protruding far beyond corniculi. Rostral setae smooth, thin and needle-like, h1 and h2 shorter than h3 and pc (h1 24–33 μm, h2 18–23 μm, h3 49–58 μm, pc 41–50 μm), distances between bases of h1–h3 approximately equal. Epistome subtriangular, apically narrowed and pointed, with a cluster of lance-like processes in lateral and ventral subapical parts (Fig. 13B). Middle article of chelicerae 110–118 μm long, with relatively short digits; movable digit 25–35 μm long, distinctly longer than fixed digit, with long, sharp and strongly curved terminal hook and three recurved teeth; fixed digit slightly shortened, 18–22 μm long, with indistinct terminal hook, very small subterminal tooth and columnar base bearing minute pilus dentilis at apex (Figs 9A, 9B); dorsal seta short, barely observable. Palpus with the following setation: trochanter, femur, tibia and tarsus with 2, 5, 6, 7 and 14 setae, respectively; ventral palptrochanter with cushion-shaped (or petal-like) swollen membranous projection (sometimes preventing some hypostomal structures from being recognized and observed), 45–55 μm long and 25–40 μm wide (Fig. 8A); palptarsus with two-tined apotele.
Legs (Figs 2A, 10C). All legs shorter than idiosoma, with well-developed praetarsus and ambulacral apparatus including pulvillus and two claws; legs I with pulvillus and claws slightly smaller than on other legs, longer or similar in length to legs IV; anterior margin of coxae II with sharp spine; legs I 515–575 μm, legs II 420–470 μm, legs III 390–440 μm, legs IV 515–570 μm long. Chaetotaxy of the legs: leg I—coxa (2), trochanter 1-1/3-1 (6), femur 2-3/1, 2/3-2 (13), genu 2-3/2, 2/1-2 (12), tibia 2-3/2, 2/1-2 (12); leg II—coxa (2), trochanter 1-0/3-1 (5), femur 2-3/1, 2/2-1 (11), genu 2-3/1, 2/1-2 (11), tibia 2-2/1, 2/1-2 (10); leg III—coxa (2), trochanter 1-1/3-0 (5), femur 1-2/1, 1/0-1 (6), genu 2-2/1, 2/1-1 (9), tibia 2-1/1, 2/1-1 (8); leg IV—coxa (1), trochanter 1-1/3-0 (5), femur 1-2/1, 1/0-1 (6), genu 1-2/1, 2/0-1 (7), tibia 1-1/1, 2/1-1 (7); tarsi II–IV with 18 setae. Leg setae smooth and mostly needle-shaped, only ventral setae of genua III–IV, tibiae II–IV and tarsi II–IV moderately thickened, spine-shaped; and apicodorsal setae (ad1, pd1) of tarsi II–IV thin and slightly widened at the end, each with narrow lanceolate tip; genua III and IV and femora III and IV neither with conspicuously elongated and distally attenuated macrosetae, nor with conspicuously thickened or elongated dorsal setae ad1 and ad2 on femora IV (Fig. 10C).
Male (Figs 2B, 4B, 7A, 8B, 9C, 10B, 10D). Idiosoma 700–780 μm long, 490–540 μm wide (n = 7; Fig. 2B). Podonotal shield 350–415 μm long and 440–540 μm wide, laterally fused with peritrematal shields located ventrally at anterolateral margins; opisthonotal shield 340–385 μm long and 440–535 μm wide, laterally and posteriorly extensively united with ventral shield. Dorsal setation and ornamentation similar to female, with the following exceptions: all dorsal setae on podonotal and opisthonotal shields (no setae on soft integument), punctation and rugosity in both shields clearly reduced and reticulation also well developed in posterior part of opisthonotal shield. Sternitogenital shield as in Fig. 7A, 260–310 μm long, with well-developed endopodal corners between coxae II–III and III–IV, reticulate pattern and four pairs of sternal setae, of which st4 apparently longest (st1 35–44 μm, st2 and st3 36–46 μm, st4 60–69 μm); genital setae (st5 33–49 μm) on separate triangular plates adjacent to the most posterior part of sternitogenital shield. Ventral shield with straight anterior margin (without incisions) and the same number of opisthogastric setae as in female. Gnathosoma relatively shorter and wider than in female, with similar features as in female; cushion-like (or petal-like?) membranous projection on palptrochanter slightly larger than in female, 60–70 μm long, 37–50 μm wide. Length of rostral setae as follows: h1 25–30 μm, h2 16–21 μm, h3 50–55 μm, pc 46–51 μm. Middle article of chelicerae apparently more robust than in female, 135–145 μm long, gradually widened proximally; movable digit 47–53 μm long, with strong terminal hook, large medial tooth and spermatodactyl; spermatodactyl relatively short, 35–45 μm long, directed anteriorly and not reaching terminal part of movable digit, curved and horn-shaped, apically tapered and bluntly pointed, sperm duct thin and placed close to ventral side; fixed digit conspicuously shortened, 20–25 μm long, with one tooth often larger than short terminal hook, and minute pilus dentilis placed on small columnar base (Fig. 9C). Legs II spurred (Figs 2B, 10D): femur, genu, tibia and tarsus with anteroventral seta modified into highly sclerotized structure formed as a robust and superficially striated spur (femur), semiglobular tubercle on slightly elevated surface (genu) or small, suboval, flat and concave tubercle (tibia, tarsus); femur II with another conspicuous ventrolateral projection posteriad to ventral spur (Fig. 10D); sexual dimorphism of dorsal setae of femur IV and genu IV not developed (Figs 10B, 10C). Other characteristics as in female.
Deutonymph (Figs 2C, 8D, 9D, 10A, 11–13A, 13C–E). Dorsal idiosoma (Figs 11, 13A). Idiosoma 495–635 μm long, 330–455 μm wide (n = 10), elongate, suboval, with the same number of setae as in adults, covered by two dorsal shields; in mature deutonymphs probably before molting, idiosoma conspicuously expanded laterally, subcircular, not completely covered by shields. Podonotal shield 260–305 μm long, 265–325 μm wide, subpentagonal, with indistinct or only faintly indicated medial scleronodules at level of s5 and 20 pairs of setae (j1 and r3 on soft integument outside shield). Opisthonotal shield 230–300 μm long, 260–315 μm wide, with similar pattern as in female, except for presence of four pairs of marginal setae (R2 – R5 on soft integument adjacent to lateral margins of shield). Surface of dorsal shields well reticulated in the narrow lateromarginal parts, remaining surface densely punctate. Most dorsal setae almost rod-shaped, sparsely barbed and each with a club-shaped apex, except for simple, mostly short and always needle-shaped setae z1, r4, J5, Z4 and R1 – R5; setae j1, z6, s2, r2, J5, Z5, S1 and S4 varying in shape of their apical part, either needle-shaped or club-shaped; z3 and s1 rarely needle-shaped; S5 elongate and whip-like, as in female. Soft integument conspicuously and densely striate. Lengths of selected dorsal setae as follows: j1 27–35 μm, j2 and j3 32–42 μm, j4 and j5 25–31 μm, j6 28–35 μm, z1 16–21 μm, z2 55–63 μm, z5 26–34 μm, z6 19–28 μm, s1 25 –30 μm, s5 56 –66 μm, s6 60 –70 μm, r3 70–91 μm, J1, J2 and J4 28–37 μm, J3 26–35 μm, J5 15–21 μm, Z1 49–57 μm, Z2 45–53 μm, Z3 36–42 μm, Z4 16–22 μm, Z5 53–67 μm, S1 26 –32 μm, S2 49 –60 μm, S3 42 –50 μm, S4 27 –33 μm, S5 275–350 μm, R1 34–42 μm, R2 and R3 23–29 μm, R4 and R5 21–26 μm.
Ventral idiosoma (Fig. 12). Sternal shield 230–270 μm long, 92–112 μm wide (at widest part of st2 or iv2), with a specific reticulate-rugose pattern of ornamentation, weakly sclerotized and transversely striate presternal plates and four pairs of setae (st1–st4); sternal setae st5 on soft integument adjacent to posterior end of shield (Figs 13C, 13D). Seven pairs of opisthogastric setae (Jv1–Jv3, Jv5, Zv1–Zv3), all arranged on soft integument. Anal shield 90– 120 μm long, 72–87 μm wide, subcircular, well rounded anteriorly, straight to slightly curved laterally, moderately convex posteriorly, with reticulate pattern predominated by concentric lines and three circumanal setae; cribrum with a row of denticles. A pair of narrow and elongate metapodal platelets, 42–48 μm long. Peritreme with only a few narrow fragments of peritrematal shield in anterior and submedial parts, not connected to podonotal shield, with anterior tip near seta s1. Lengths of selected ventrally located setae as follows: st1 and st2 20–26 μm, st3 18–23 μm, st4 and st5 12–18 μm, ad 26–34 μm, pa 16–20 μm, Jv5 30–40 μm.
Gnathosoma (Figs 8D, 9D, 13E). Anterior margin of epistome subtriangular, with many fimbriae on laterodistal margins (Fig. 13E). Deutosternum of gnathosoma (Figs 8C, 8D) as in adults, except for length of rostral setae (h1 10–14 μm, h2 9–13 μm, h3 17–22 μm, pc 22–27 μm). Chelicera similar to female (Fig. 9D), 85–95 μm long (movable digit 25–30 μm long, fixed digit 16–21 μm long). Other characteristics as in adults.
Legs (Figs 2C, 10A). All legs shorter than idiosoma: legs I 420–450 μm, legs II 345–390 μm, legs III 335–395 μm, and legs IV 425–465 μm long. Setation as in adults, but ventral setae not as conspicuously thickened, and apicoventral setae (av1 and pv1) of tarsi II–IV thin, needle-like and subapically arranged (these setae are short spines in adults and are located at the very end of the tarsi). Dorsal and lateral setae of femur, genu and tibia of legs IV needle-like, as in Fig. 10A.
Type material
Holotype female: Slovakia, Little Carpathians Mountains, Lozorno Village, Ohek Mt., beech forest, in decomposing fruiting body of Fomes fomentarius (Basidiomycota: Polyporales) growing on a trunk of Fagus sylvatica and infested by Neomida haemorrhoidalis (Fabricius) (Coleoptera, Tenebrionidae), elevation 350 m, September 10, 2024. Paratypes: six females, three males and 32 deutonymphs—with the same collection data as in the holotype, but the deutonymphs were found on beetles of N. haemorrhoidalis; one female, two males — June 19, 2024, other data as in the holotype; one female — July 22, 2024, other data as in the holotype; one male — Borská Nížina Lowland, Tomky Village, Lásek Forest, pine forest with birch admixture, in old F. fomentarius on a trunk of Betula sp., elevation 190 m, September 1, 2023; one male — Borská Nížina Lowland, Vysoká Pri Morave Village, Horný Les Forest, hard floodplain forest, in F. fomentarius on a trunk of Quercus sp., elevation 145 m, July 15, 2024; one female, 12 deutonymphs— Tríbeč Mountains, Skýcov Village, Prostredný Vrch Mt., deciduous forest, in F. fomentarius on a trunk of F. sylvatica (female), on beetles of N. haemorrhoidalis (deutonymphs), elevation 480 m, June 4, 2024.All these specimens were collected by the author and are deposited in the Institute of Zoology of the Slovak Academy of Sciences, Bratislava, Slovakia.
Etymology
The specific name of this species refers to its phoretic association with the darkling beetle of the genus Neomida Latreille.
Ecological notes
A specific phoretic host for Bulbolaelaps neomidae, the tenebrionid Neomida haemorrhoidalis, is a Euro-Siberian species that lives and reproduces in the fruiting bodies of various xylotrophic fungi, mainly Fomes fomentarius. Both this beetle and its main host, the fungus F. fomentarius, have increased their occurrence and abundance due to the considerable increase of dead wood in Slovak forests. According to some authors (Burakowski et al. 1987; Müller et al. 2005), it is a rare species that only occurs in very well-preserved or primeval deciduous forests. Larvae and adults are obligate fungivores and inhabit old fruiting bodies in the later stages of decomposition.
The occurrence of Bulbolaelaps neomidae is not rare in Slovakia, and its deutonymphs are very likely to be found in suitable fruiting bodies of the tinder fungus Fomes fomentarius directly on the beetles Neomida haemorrhoidalis. The new mite has not been detected on other species of polypores or host beetles. The deutonymphs are relatively large and can easily be found, especially on relatively small and characteristically colored host beetles, even in large numbers. If no N. haemorrhoidalis beetles are present in the fruiting bodies of tinder fungi, we could not even detect the presence of B. neomidae mites in them. Beetles and their mites mainly inhabit very old sporocarps previously infested by larvae of various fungivorous insects, but also dead fruiting bodies in an advanced stage of decomposition containing detritus with a high content of dusty residues.
Obtaining the adult stages of the mite was a time-consuming and laborious activity that remained unsuccessful for a long time. In contrast to the two other reported species, none of the collected adults were found on the surface of the colonized fruiting bodies, but exclusively inside them. When rearing the phoretic deutonymphs together with their beetle hosts in the laboratory, it was not possible to ensure the conditions for their molting and transformation into adults (the deutonymphs lived for several months and moved exclusively on the host beetles until their death). The adult mites are rare compared to the deutonymphs, and they were mostly obtained by individual collection from inside the sporocarps directly in the field and only to a small extent with Berlese-Tullgren funnels in the laboratory.
The mites were mainly collected from the upper interior of the fruiting bodies most heavily occupied by the beetles, both from the softer fleshy tissue, directly from the galleries of active beetle larvae, but also from completely dried wood substrate ground to a fine dust. It should be noted that the interior of dead fruiting bodies can develop into a very dry and inhospitable microhabitat during the summer months due to various decomposition processes and, above all, climatic factors. When the fruiting body dried in this way is handled, the contents of the dust particles accumulated during decomposition are easily released from inside the fruiting body and disperse in the form of dust clouds that escape through the holes and cracks in the fruiting body. The formation and development of the three-dimensional, swollen membranous projections near the mouthparts, which probably prevent dust particles from penetrating the mouth opening itself and adhesion to the adjacent fine structures, can be explained precisely against the background of such a specific milieu or life substrate. Similar projections have rarely been observed in other taxa of mesostigmatic mites (e.g. Reticulolaelaps Costa; Nemati et al. 2019). Interestingly, and contrary to the above assumption, the adult specimen of the only congeneric species from Iran with identical inflated membranous projections was collected on the fruiting body of a gilled fungus (possibly a Pleurotus species), which is a fundamentally different fungal species from the perennial Fomes fomentarius. Whether this is an accidental contamination or a typical occurrence of the species in Iran must be clarified by further investigations.
Taxonomic notes
The new species from Slovakia is the second known representative of the genus Bulbolaelaps and is very similar to the original species from Iran. Both species can be distinguished by the characteristics listed in the identification keys below.
description: Published as part of Mašán, Peter, 2025, Digamasellid mites (Acari: Mesostigmata) in association with saproxylic darkling beetles (Coleoptera: Tenebrionidae) and wood-decaying fungi (Polyporales) in Slovakia, pp. 1-58 in Zootaxa 5627 (1) on pages 3-7, DOI: 10.11646/zootaxa.5627.1.1, http://zenodo.org/record/15325037