Cosmolaelaps dendrophilus Davydova

Joharchi, Omid, Tolstikov, Andrei V., Khaustov, Alexander A., Khaustov, Vladimir A. & Sarcheshmeh, Mohammadhassan Abbasi, 2019, Review of some mites (Acari: Laelapidae) associated with ants and bumblebees in Western Siberia, Russia, Zootaxa 4613 (1), pp. 71-92 : 73-74

Cosmolaelaps dendrophilus Davydova

Figures 5–13 .

Cosmolaelaps dendrophilus Davydova, 1977: 23 .

Cosmolaelaps dendrophilus .— Moreira et al., 2014: 319.

Specimens examined. 14 females and one male, RUSSIA, Tyumen Province, vicinity of Uspenka, 57°04’N, 65°04’E, 21 May 2018, O. Joharchi coll., in the nest of Formica fusca L. ( Hymenoptera : Formicidae ) in the rotting stems of trees and stumps.

Here we provide morphological features of female of C. dendrophilus to complement the original description of Davydova, 1977.

Redescription. Dorsal idiosoma. Dorsal shield oval ( Fig. 5 ), length 475–520, width at level of r3, 300–335 (n=10), with 39 pairs of scimitar-shaped setae ( Fig. 7 ), 22 podonotal, 17 opisthonotal, including two pairs of Zx setae between J and Z setae; almost all setae subequal length (48–54), except Z5, j1 (20–25) spatulate-mucronate or clavate, Z5 with 2–4 minute barbs and z1 (18–20) setiform, all setae reaching past base of next posterior seta, shield with two unpaired supernumerary seta Jx between J series.

Ventral idiosoma. Sternal shield (length 97–106) narrowest between coxae II (94–97), widest between coxae II–III (151–155), with slightly concave anterior margin and straight posterior margin, with three pairs of simple, smooth, pointed setae, st1 (39–41), st2 (36–38), st3 (31–35) and two pairs of poroids (iv1 and iv2 slit-like, near to setae st1 and between st2 and st3, respectively), surface of sternal shield without reticulate ornamentation, almost smooth, except some irregular longitudinal lines laterally ( Fig. 6 ). Genital shield ( Fig. 6 ) tongue-shaped (241–245 long × 100–110 wide), surface reticulated with irregular longitudinal lines in anterior and two diagonal lines forming an inverted-V enclosing elongated oblique irregular cells in posterior part, and a pair of simple setae st5 (32–35) ( Fig. 6 ). Shield flanked by a pair of minute narrow platelets; paragenital poroids located on soft cuticle lateral to shield near seta st5. Anal shield subtriangular, anterior margin gently rounded and triangular posteriorly, length 67– 72, width 78–80, anterior half with lineate ornamentation, with a pair of lateral pores (gv3), para-anal setae (19–22) longer and thicker than post-anal seta (24–26), cribrum small ( Figs 6, 8 ). Soft opisthogastric cuticle surrounding genital and anal shields with 15 pairs of setae (Jv1–Jv5, Zv1–Zv5, R1–R4, UR1), and three pairs of poroids (ivo). Setae Jv5, Zv4, Zv5, R1–R4 and UR1 scimitar-shaped (17–20), setae Jv1–Jv4, Zv1–Zv3 simple (25–28). Peritremes long, extending to the mid-level of coxa I, peritrematal shield narrow, free from exopodal shields, limited essentially to protrusion band of cuticle lateral to the peritreme at the level of coxae II–III, each shield bearing five discernible pore-like structures, a lyrifissure ip and a gland pore gp at level of coxa II, two lyrifissures ip and a gland pore gp on post-stigmatic section, and a small pore-like structure within peritreme at level of coxa III (see Fig. 6 ); anterior part of shield fused with dorsal shield. Peritrematal shield free posteriorly, post-stigmatal section narrow, with three pairs of discernible pore-like structures (two lyrifissures ‘ ip’, and one gland pore ‘ gp’).

Gnathosoma . Epistome arched with denticulated anterior margin. Hypostomal groove with six transverse rows of denticles, each row with about 10–20 small teeth, and smooth anterior and posterior transverse lines. Chaetotaxy of palps: trochanter 2, femur 5, genu 6, tibia 14, tarsus 15, all setae smooth and needle-like except al on palp femur and genu thickened, apically spatulate, palp tarsal claw two-tined. Fixed digit of chelicera with five teeth varing sizes ( Fig. 9 ), pilus dentilis short and slender, dorsal seta short, semi-erect, movable digit with two large subterminal teeth.

Legs.Tarsi I–IV each with a pair of claws and pulvillus. Legs II (377–389) and III (328–339) shorter than legs I (474–477) and IV (508–517). Chaetotaxy normal for free-living Laelapidae : Leg I: coxa 0 0/1 0/1 0, trochanter 1 0/1 1/2 1, femur 2 2/1 3/3 2 (ad1, pd2, pd3 thickened), genu 2 3/2 3/1 2 (dorsal setae thickened, ad2 inserted on small tubercle), tibia 2 3/2 3/1 2. Leg II: coxa 0 0/1 0/1 0, trochanter 1 0/1 1/1 1, femur 2 3/1 2/2 1 (ad1 and pd2 spatulate; pd2 longer than the others (34–37), Fig. 10 ), genu 2 3/1 2/1 2 (dorsal setae thickened), tibia 2 2/1 2/1 2. Leg III: coxa 0 0/1 0/ 1 0, trochanter 1 0/1 1/1 1, femur 1 2/1 1/0 1 (ad1 spatulate, Fig. 11 ), genu 2 2/1 2/1 1, tibia 2 1/1 2/1 1. Leg IV: coxa 0 0/1 0/0 0, trochanter 1 1/1 0/1 1 (ad1 spatulate, Fig. 12 ), femur 1 2/1 1/0 1 (ad1 and ad2 spatulate, Fig. 12 ), genu 2 2/1 3/0 1 (most setae relatively thick), tibia 2 1/1 3/1 2 (most setae relatively thick). Tarsi II–IV with 18 setae 3 3/2 3/2 3 + mv, md, all setae simple and needle-like; all pre-tarsi with a well-developed ambulacral stalk, a pair of claws and three rounded pulvillar lobes, extensively projecting beyond claws.

Notes. Cosmolaelaps dendrophilus was described from Novosibirsk, Western Siberia, Russia ( Davydova, 1977). The description of this species is brief and both the description and illustrations lack many important details. It has been found on rotting stems of trees and stumps and is now recorded in Tyumen Province, from the nest of Formica fusca L. in the rotting stems of trees and stumps. Also, we have studied detailed photos of two females on the slide (No. 115, 27.VII.1967) of the Davydova Collection deposited at the Siberian Zoological Museum, Novosibirsk, Russia. This species most resembles Cosmolaelaps vacua ( Michael, 1891) sensu Evans & Till (1966 , Fig. 27 ) and C. thysanifer Zeman, 1982 but differs from both species by the different shape of j1 and Z5 setae, spatulate-mucronate and clavate form, respectively, Z5 with 2–4 minute barbs ( Figs 5, 7, 8 ) (vs. both setae simple and smooth in C. vacua ; setae j1 scimitar-like and Z5 brush-like in C. thysanifer ). Evans & Till (1966) did not provide any information about the shape of the leg setae, but according to the original description ( Michael, 1891) of Cosmolaelaps vacua, femora II and IV bear two spatulate setae (Karg, 1981, Fig. 8a, also illustrated this character). In Cosmolaelaps dendrophilus, femora II and IV bear two spatulate setae (ad1, pd2 on femur II and ad1, 2 on femur IV), and ad1 on femur III and trochanter IV are also spatulate in form (see Figs 11, 12). Davydova (1977, Fig. 2) described and illustrated the male of C. dendrophilus, and shows the ventrianal region of holoventral shield with a strongly sclerotised median projection. This structure is also described in heteromorphic males of C. vacua (Gwi- azdowicz, 2004), but is not present in our examined specimen, so our examined male is not heteromorphic. In the chelicera of C. dendrophilus illustrated by Davydova (1977, Fig. 2e), the spermatodactyl is mostly straight, slightly sinuate and 60% of its length is free from the movable digit. We examined the same structure in our male specimen (Fig. 13) but in the chelicera of C. vacua and C. thysanifer provided by Michael (1891, Fig. 7a) and Zeman (1982, Fig. 6B), respectively, the spermatodactyl is mostly curved downward but bent upward at the tip, and about 40% of its length is free from the movable digit in both species. On the other hand, Hirschmann et al. (1969) described and illustrated the female and male of Hypoaspis (Cosmolaelaps) serratosimilis, and Bregetova (1977) then con- sidered that Hypoaspis (Cosmolaelaps) serratosimilis is a synonym of C. vacua, without providing any supporting evidence. Karg (1981 and later papers) and Gwiazdowicz (2004) also followed Bregetova’s concept. The evidence from both the males and females strongly suggests that different authors have used the name C. vacua to refer to several different species.

Figures

FIGURES 5–13. DIC micrographs of Cosmolaelaps dendrophilus, female. 5, idiosoma in dorsal view, enlarged section not to scale; 6, idiosoma in ventral view; 7, general view of some dorsal setae; 8, general view of setae Z5 and anal shield; 9, chelicera, fixed digit; 10, femur leg II; 11, femur leg III; 12, femur and trochanter leg IV; male. 13, chelicera.

FIGURES 26–34. DIC micrographs of Cosmolaelaps siberiensis sp. nov., female. 26, idiosoma in dorsal view; 27, idiosoma in ventral view; 28, general view of some dorsal setae, 29, genital and anal shields, general view of some opisthogastric setae; 30, genital and sternal shields; 31, epistome; 32, subcapitulum; 33, chelicera, fixed digit; 34, palp and apotel.