Nidilaelaps cubaensis, Joharchi & Ermilov, 2023

Joharchi, Omid & Ermilov, Sergey G., 2023, A new species of the genus Nidilaelaps Shaw (Acari: Mesostigmata: Laelapidae) from Cuba, Persian Journal of Acarology 12 (2), pp. 249-257 : 250-255

Nidilaelaps cubaensis sp. nov. ( Figs. 1–14 )

http://zoobank.org/ urn:lsid:zoobank.org:act:5F3B4E1C-DB69-4451-870B-25CC002849C

Type material

Holotype, female, Cienfuegos Province, Sierra del Escambray , El Nicho, Cuba, 22° 1′ N, 80 °7′ W, collected from forest litter (collector and date of collection unknown) . Paratypes, two females, same data as holotype .

Diagnosis (adult female)

Dorsal shield covering idiosoma, suboval, slightly extending onto ventrolateral aspect of idiosoma, with 40 pairs of smooth setae (except Z5 and J5, with a few barbs), including three pairs of Zx, and three unpaired (Jx) setae; dorsal setae long, reaching well past base of next posterior setae, homogeneous in length and thickness; presternal area weakly sclerotized, sternal shield with reticulate ornamentation throughout, except central and posterior parts faintly reticulated, anterior margin of shield undulating, posterior margin slightly concave; genito-ventral shield bottle-shaped, long, broadly abutting anal shield, bearing setae st5 and Zv1 and two additional pairs of setae (Jv1–2) on its margins (flanking shield), shield ornamented posteromedially by 7–9 broad transverse cells; anal shield subtriangular, subequal in length and width, post-anal seta slightly longer than para-anal setae; fixed digit of chelicera with five teeth (including an offset subapical tooth, gabelzhan); all leg setae simple, acicular, legs I and IV longer than length of idiosoma.

Description (Female, n = 3)

Dorsal idiosoma ( Figs. 1 , 6 ) – Dorsal shield 570–600 long, 420–450 wide, covering idiosoma, suboval, slightly extending onto ventrolateral aspect of idiosoma, shield with weak reticulation, more distinct in opisthonotal and lateral regions (posterior to J1), with 40 pairs of smooth setae (except Z5 and J5, with a few barbs): 22 pairs of podonotal setae, 18 pairs of opisthonotal setae, including three pairs Zx, and three unpaired (Jx) setae. Dorsal setae long (70–95), reaching well past base of next posterior setae, homogeneous in length and thickness, except j1 (40–43), z1 (19–21) shortest ( Figs. 1 , 6 ). Shield with about 21 pairs of discernible pore-like structures, including 16 poroids (id1, id2, id4-id6, idm-idm6, is1, idx, idl1, idl3, idl4) and five gland openings (gd1, gd5–6, gd8–9), others indistinct.

Ventral idiosoma ( Figs. 2 , 7, 8 ) – Tritosternum with paired pilose laciniae (105–108), fused basally (20–22), columnar base 33–35 × 18–20 wide; presternal area lightly sclerotized, fused to sternal shield; sternal shield length 125–130, maximum width 185–195, narrowest between coxae II (119–123), with distinct reticulate ornamentation over whole surface, except posterior area between setae st2–st3, where overlapped by hyaline flap of genital shield smooth or faintly reticulated ( Figs. 2 , 7 ), anterior margin of shield undulating, posterior margin slightly concave, remnants of gland pores gv1 apparent near posterior shield margin; bearing three pairs of smooth setae (st1–3) (48–52), almost reaching base of next setae, and two pairs of poroids, iv1 and iv2 slit-like, adjacent to setae st1 and between st2 and st3, respectively. Metasternal platelets absent; metasternal setae st4 (50–52) and metasternal poroids located on soft integument. Endopodal plates between coxae I–II (bearing gland pores gvb) and II–III completely fused to sternal shield, endopodal plates III/IV elongate, narrow and curved. Genito-ventral shield bottle-shaped, expanded, broadly abutting anal shield, length 330–350, maximum width 215–225, posterior margin rounded, shield ornamented posteromedially by 7–9 broad transverse cells, bearing setae st5 (55–57) and Zv 1 (69–72) and two additional pairs of setae (Jv1–2) (63–66) on its margins (flanking shield) ( Figs. 2 , 7, 8 ), paragenital poroids iv5 located on soft cuticle lateral to shield (on its margins) near seta st5 ( Figs. 2 , 7, 8 ). Anal shield subtriangular, subequal in length and width (length 93–98, width 95–100), post-anal seta (48–50) slightly longer than para-anal setae (33–35), anterior half lineate-reticulate, cribrum consisting of a terminal tuft with 3–4 irregular rows of spicules and a pair of anterior arms reaching level of posterior margin of anus ( Figs. 2 , 7 ); anal gland pores (gv3) on lateral margin of anal shield, slightly posterior of level para-anal setae. Soft opisthogastric cuticle with pair of elliptical metapodal plates (35–38 long × 8–10 wide), and 15 pairs of smooth setae (Jv1–Jv5, Zv2–Zv 5, R1–R4, UR, r6) (54–60). Peritrematal shield well developed, bearing one gland pores (gd3) and one poroid (id3) at level near coxae II–III, poststigmatic extension of shield with two pairs of poroids (id7 & ip) and one pair of gland pores (gp) ( Figs. 2 , 7 ); anterior region of peritrematal shield fused to anterior margin of dorsal shield behind setae z1 ( Figs. 2 , 7 ). Peritremes relatively long, extending to mid-level of coxae I ( Figs. 1, 2 , 6, 7 ). Parapodal element behind coxae IV relatively thick and bearing gland pore gv2, fused to exopodal plate flanking coxae II–IV ( Figs. 2 , 7 ).

Gnathosoma ( Figs. 3–5 , 9–10 ) – Epistome subtriangular, smooth, with pointed apex ( Fig. 4 ). Hypostomal groove with six transverse rows of denticles, each row with 8–13 tiny denticles, with smooth anterior and posterior transverse lines ( Fig. 4 ). Hypostome with four pairs of smooth setae, h3 (52–55)> h1 (46–49)> pc (33–36)> h2 (18–20) ( Fig. 3 ). Corniculi robust and horn-like, extending beyond palptrochanter. Internal malae longer than corniculi, comprising a pair of pilose median projections, and 6–8 lateral, tentacle-like, smooth projections; labrum with pilose surface ( Fig. 3 ). Chaetotaxy of palps ( Fig. 10 ): trochanter 2, femur 5, genu 6, tibia 14, tarsus 15, all setae smooth; palp tarsal apotele two-tined ( Fig. 10 ). Fixed digit of chelicera with an offset distal tooth (gabelzahn), followed by four teeth, a setaceous pilus dentilis, dorsal cheliceral setae prostrate, arthrodial membrane with a rounded flap and normal filaments; cheliceral dorsal and lateral lyrifissures distinct; movable digit with two teeth ( Figs. 5 , 9 ).

Legs ( Figs. 11–14 ) – Legs II (464–475) and III (460–470) short, I (780–800) and IV (713–725) longer. Chaetotaxy normal for free-living Laelapidae : Leg I ( Fig. 11 ): coxa 0-0/1, 0/1-0, trochanter 1-0/1, 1/2-1 (pd slightly thickened), femur 2-2/1, 3/3-2 (av and all dorsal setae slightly thickened), genu 2-3/2, 3/1-2, tibia 2-3/2, 3/1-2. Leg II ( Fig. 12 ): coxa 0-0/1, 0/1-0, trochanter 1-0/1, 0/2-1, femur 2-3/1, 2/2-1 (ad1 slightly thickened), genu 2-3/1, 2/1-2, tibia 2-2/1, 2/1-2. Leg III ( Fig. 13 ): coxa 0- 0/1, 0/1-0, trochanter 1-1/2, 0/1-0 (ad slightly thickened), femur 1-2/1, 1/0-1, genu 2-2/1, 2/1-1, tibia: 2-1/1, 2/1-1. Leg IV ( Fig. 14 ): coxa 0-0/1, 0/0-0, trochanter 1-1/1, 0/1-1, femur 1-2/1, 1/0-1, genu 2- 2/1, 3/0-1, tibia 2-1/1, 3/1-2. Tarsi II-IV with 18 setae (3- 3/2, 3/2-3 + mv, md); with some ventral and lateral setae slightly thickened ( Figs. 11–14 ). All pretarsi with paired claws, rounded pulvilli, and a long thin stalk.

Insemination structures – Not seen, apparently unsclerotised.

Etymology The specific name is derived from the country of origin, Cuba.

Remarks

Shaw (2012) erected the genus Nidilaelaps to accommodate three species, including N. annectans (the type species) that had previously been placed either in Pseudoparasitus or Gymnolaelaps , and recorded from mammals, birds, or their nests in Papua New Guinea and Australia ( Womersley 1955; Evans and Till 1966; Domrow 1973; Shaw 2012). Afterwards, Joharchi et al. (2021) reported this genus for the first time from Afrotropical realm, based on specimens identified as N. annectans , collected from a native habitat at Nightingale Island and from imported stored food at Tristan Da Cunha Island. Since that time, there has been no other formal recording of Nidilaelaps in the world; in this publication a species of this genus is recorded for the first time in the Caribbean region. Nidilaelaps is superficially similar in its morphology to Ulyxes Shaw , Androlaelaps Berlese , Haemolaelaps Berlese , Pseudoparasitus Oudemans and Gymnolaelaps Berlese but this problem was comprehensively discussed by Shaw (2012, 2014). We consider N. cubaensis to be a member of Nidilaelaps because this species agrees well with Nidilaelaps in the following main character states: dorsal shield covering entire dorsum, holotrichous, with rather long dorsal setae, including 1–3 medial accessory Jx setae, having weakly sclerotized presternal area, without well-defined platelets, genito-ventral shield extensive (broad and long), bottle-shaped, abutting anal shield, shield ornamented posteromedially by 7–9 broad transverse cells and bearing setae inserted on or near the shield margins (not far inwards), paragenital poroids iv5 located on soft cuticle lateral to shield (on its margins, not on shield); smooth epistome, 2-tined palp tarsal claw, normal shape of pilus dentilis, all leg setae simple, acicular, not barbed or apically bifid, genu IV pd seta fine and hence homomorphic with ad1–2, not stout, genua III and IV each with 9 setae (pl2 absent). Nidilaelaps cubaensis sp. nov. most closely resembles N. holdsworthi Shaw, 2012 [first couplet in the identification key to Nidilaelaps species provided by Shaw (2012)], due to the insertion of st5 and Zv 1 in the genito-ventral shield, but N. cubaensis sp. nov. can be easily distinguished from N. holdsworthi and the two other described congeners by having 40 pairs of smooth setae on dorsal shield, including three pairs of Zx, and three unpaired (Jx) setae (versus dorsal shield bearing 39 pairs of setae (including two pairs Zx setae) in the other species) and fixed digit of chelicera with five teeth (versus fixed digit of chelicera bearing less than five teeth in those species). Shaw (2012: 26) was unsure about the subfamilial placement of this genus, stating that the phoretical association with vertebrates places it in the Laelapinae , while the apparent predatory behaviour places it in the Hypoaspidinae. Nothing is known about the feeding habits or other aspects of the behaviour of this genus, and it is not possible to draw firm conclusions about the biology or host specificity of individual Nidilaelaps species, but their normal morphology (as other free-living Hypoaspidinae genera) - e.g. strong chelicerae with well-developed teeth, sclerotized and horn-like corniculi - suggests that they may be a predator of small invertebrates. So it seems unlikely that they are vertebrate parasites. We stress that further experimental work is needed to establish the true role of this mite in its respective ecosystems.

Figures

Figures 1–5. Nidilaelaps cubaensis sp. nov. (female) – 1. Dorsal idiosoma; 2. Ventral idiosoma; 3. Subcapitulum; 4. Epistome; 5. Chelicera, lateral view.

Figures 6–10. DIC micrographs of Nidilaelaps cubaensis sp. nov. (female) – 6. Idiosoma in dorsal view; 7. Idiosoma in ventral view; 8. Genito-ventral shield; 9. Chelicera, lateral view; 10. Distal portion of palp, ventrolateral view, with a focus on apotele.

Figures 11–14. Nidilaelaps cubaensis sp. nov. (female) – 11. leg I (trochanter-tibia); 12. leg II (trochanter-tarsus); 13. leg III (trochanter-tarsus); 14. leg IV (trochanter-tarsus).