Lobogynium sudhiri (Datta) Datta, 2012

Plumari, Massimo & Kazemi, Shahrooz, 2012, Redescription and neotype designation of Lobogynium sudhiri (Datta) (Acari: Diplogyniidae), a mite associated with beetles of the genus Atholus (Thomson) (Coleoptera: Histeridae) in the Palaearctic region, Zootaxa 3352, pp. 1-16 : 6-12

publication ID	https://doi.org/ 10.5281/zenodo.208412
DOI	https://doi.org/10.5281/zenodo.6171894
persistent identifier	https://treatment.plazi.org/id/FD74EA00-F017-E22E-E8DE-FF37FC30C3D7
treatment provided by	Plazi
scientific name	Lobogynium sudhiri (Datta)
status	comb. nov.

Treatment

Lobogynium sudhiri (Datta) comb. n.

Ophiocelaeno sudhiri Datta, 1985: 44 .

Diagnosis (adults). With the characteristics of the genus. Species of large size, reddish-coloured. Four pairs of long dorsal setae in medio-lateral series (z3, z6, Z2 and Z4) ( Fig. 1 View FIGURE 1 ). Sternal setae st2 about in the middle of the shield, and st3 at base of postero-lateral prolongations ( Fig. 4 View FIGURE 4 A). Metasternal shields fused entirely into a single plate along their medial margins, lacking posterior prolongations ( Fig. 4 View FIGURE 4 E). Antero-lateral portion of latigynal shields folded to form an ear-shaped dorsal lobe; mesogynal shield about one-half as long as latigynal shields ( Fig. 4 View FIGURE 4 B). Distance between ventral setae JV2 almost equal to distance between setae JV2 and anterior margin of anal opening ( Figs 3 View FIGURE 3 , 5 View FIGURE 5 ); distance between ventral setae JV2 and ZV2 shorter than distance between setae ZV2 and lateral margin of ventri-anal shield ( Figs 3 View FIGURE 3 , 5 View FIGURE 5 ); antero-lateral circum-anal area strongly sclerotised ( Figs 3 View FIGURE 3 , 5 View FIGURE 5 , 8 View FIGURE 8 ); ventri-marginal shields very wide with one glandular complex on posterior end ( Figs 3 View FIGURE 3 , 5 View FIGURE 5 , 8 View FIGURE 8 ); peritremes with a distinct inward bend at level of coxae II–III ( Figs 3 View FIGURE 3 , 5 View FIGURE 5 , 8 View FIGURE 8 ). Palp femur with long stout setae d1 and d2 and spur-like seta al; seta d1 inserted on a large truncated dorsal process ( Fig. 2 View FIGURE 2 B). Male with two porose areas near genital opening ( Figs 5 View FIGURE 5 , 6 View FIGURE 6 C, 6D, 6E). Movable digit of the male chelicera with spoon-like process ( Fig. 6 View FIGURE 6 B).

Description. Female ( Figs 3 View FIGURE 3 , 4 View FIGURE 4 , 8 View FIGURE 8 A) (10 specimens measured).

Dorsal idiosoma ( Fig. 1 View FIGURE 1 ). Dorsal shield 998 ± 43 (920–1055) long, maximum width 843 ± 36 (790–890), ratio length/width 1.20 ± 0.06 (1.12–1.33). Podonotum with 24 pairs of setae and one small unpaired seta (j 2): five dorso-central (j1, j3-j6), five medio-lateral (z1-z3, z5-z6), six lateral (s1-s6), five marginal (r2-r6), two additional pairs between dorso-central and medio-lateral series (jx1-jx2) and one additional pair in marginal series (rx). Opisthonotum with 19 pairs of setae: five dorso-central (J1-J5), five medio-lateral (Z1-Z5), four lateral (S1-S3, S5) and five marginal (R1-R5). Setae z3, z6, Z2 and Z4 (175) the longest and with barbed tip, z3, z6 and Z2 curved. Setae j3- j6, jx1, jx2, Z1, J1 and J2 vestigial. Setae j2, z2, s2-s6, S1-S3, Z3, J3 and J4 short (19). Setae, j1 (38), z1 (18), s1 (21), r2-r6, rx and R1-R5 (34), and J5 (29) longer and spine-like, S5 (81) and Z5 (96) lancet-like. Several pore-like structures of different size: three dorso-central, two medio-lateral and six submarginal pairs of lyrifissures; many small pores irregularly scattered over entire dorsal shield; 12 pores greater with symmetric distribution along each lateral margin; some glandular complexes in posterior region of opisthonotum. Dorsal ornamentation with irregular polygons; one faint transversal line laterally incomplete and about in the middle of the shield, and one short cleft in the middle of the posterior margin.

Ventral idiosoma ( Figs 3 View FIGURE 3 , 4 View FIGURE 4 A, 4B, 4E, 8A). Tritosternum hyaline with two free laciniae ( Fig. 3 View FIGURE 3 ). Sternal shield ( Fig. 4 View FIGURE 4 A) 128 ± 8 (113–143) long in midline, 238 ± 8 (225–250) wide between antero-lateral corners; anterior corners oblique, postero-lateral prolongations broad, ending between coxae II and III; anterior and posterior margins weakly and deeply concave respectively; anterior and lateral margins with dorsal fold very broad along anterior margin, and fused laterally with endopodal shields II; three pairs of smooth setae, two pairs of lyrifissures and one pair of pores; st1 (38) along anterior margin and near lyrifissures I, st2 (24), pores and lyrifissures II about in the middle of the shield, st3 (24) at base of postero-lateral prolongations. Metasternal shields fused entirely in a single plate along their medial margins, separated completely from sternal shield and lacking in posterior prolongations, setae and pores; metasternal plate clearly visible between sternal and latigynal shields, and jointed with well sclerotised club-like vaginal sclerites, with medial thorn-like projections ( Fig. 4 View FIGURE 4 E). Latigynal shields harp-shaped with two pairs of setae (19), one pair of pores and antero-lateral portion folded to form an ear-shaped dorsal lobe, concealed by sternal postero-lateral prolongations; anterior pair of setae in antero-lateral corners and posterior pair near postero-lateral corners; mesogynal shield about one-half as long as latigynal shields that partially conceal it ( Fig. 4 View FIGURE 4 B). Ventri-anal shield fused with peritrematal, exopodal and endopodal III-IV shields, not extending to posterior margin of idiosoma, anterior margin deeply concave and thickened, with six pairs of setae, 11 pairs of porelike structures and three to four pores (with asymmetric distribution anterior to anal opening): one intercoxal seta (25), four pre-anal JV1 (49), JV2 (20), JV3 (34), ZV2 (36) and one post-anal JV5 (30) pairs of setae, two pores and two lyrifissures para-axial to either peritreme, one pair of smaller pores near the anterior margin of the ventri-anal shield, one pair of larger pores anterior and one posterior to JV1, one pair of smaller pores anterior and one posterior to JV3, one pair of smaller pores anterior to JV5 and two large slit-like lyrifissures at level of the shield posterior end; distance between ventral setae JV2 almost equal to distance between setae JV2 and anterior margin of anal opening; distance between ventral setae JV2 and ZV2 shorter than distance between setae ZV2 and lateral margin of ventri-anal shield; anal opening surrounded anterolaterally by strongly sclerotised cuticle; stigmata between coxae III and IV; peritremes long, extending beyond coxa I, with a distinct inward bend at level of coxae II–III ( Fig. 3 View FIGURE 3 ). Marginal shields divided from ventri-anal shield by strip of thin cuticle, with wide and truncated posterior ends meeting posteriorly to ventri-anal shield, one pair of setae (46), five lyrifissures and one glandular complex ( Fig. 3 View FIGURE 3 ). Ornamentation with irregular polygons in the sternal, genital and ventri-anal shields and posterior region of marginal shields; this ornamentation more evident in genital shields, anterior region of ventri-anal shield and posterior region of sternal shield; ornamentation with long polygonal areas in anterior and central region of marginal shields.

Gnathosoma ( Figs 2 View FIGURE 2 B, 2C, 4C, 4D). Base about twice as wide as long, with six notches on the lateral surfaces and one transverse line at base of deutosternum ( Fig. 2 View FIGURE 2 C). Hypostome with three pairs of simple setae, hyp1 (51), hyp2 (59) and hyp3 (33); gnathosomal setae short (26) and slightly barbed; corniculi horn-like, stout; whip-like hypopharyngeal (hypp) and seta-like hypostomal (hyp) processes, respectively longer and shorter than corniculi; labrum (lb) blade-like; deutosternum wider at level of gnathosomal setae, anteriorly and posteriorly more narrow, with five transverse rows, two outer rows smooth, others with denticles. Epistome triangular, with winding and smooth antero-lateral margins, pointed apex and variable number of transverse rows of denticles ( Fig. 4 View FIGURE 4 D). Palps unspecialised: trochanter with two setae (v1 and v2); femur with five setae, setae d1 (106) and d2 (84) long and stout, seta d1 inserted in truncated process, seta al spur-like, setae d3 and pl simple, seta pl longer and weakly barbed; genu with seven setae, six simple setae (v, al1, al2, pl, d2 and d3) and one spur-like seta (d1); tibia with 14 simple setae; tarsus with 15 simple setae and apotele 2-tined. Fixed digit of chelicera with 12–14 small teeth, the first proximal and the last three distal teeth arranged in different row; movable digit with six to eight small teeth and a large basal tooth, three fringed excrescences and one comb-like structure ( Fig. 4 View FIGURE 4 C).

Legs ( Figs 2 View FIGURE 2 A, 7). Leg I slender, antenniform; tarsus I polytrichous, without ambulacrum, with one small apical spiniform sensillum and a small acrotarsus; coxa I with anterolateral tubercle and denticulate antero-dorsal margin ( Fig. 2 View FIGURE 2 A). Legs II–IV relatively short and stout; tarsi II–IV with well developed rounded pulvillus and one pair of claws, antero-ventral margin with small spiniform protuberances and one small but distinct sensillum on the tip (ad1); one long dorsal seta (pd1) distally barbed on genu III (101) and IV (158) ( Fig. 7 View FIGURE 7 ). Chaetotaxy as in Table 1.

Leg Coxa Trochanter Femur Genu Tibia Tarsus I 2 6 10 (1 2/2 2/2 1) 9 (1 3/1 2/1 1) 13 (2 3/2 2/2 2)

II 2 5 10 (2 2/1 2/2 1) 9 (1 3/1 2/1 1) 7 (1 1/1 2/1 1) 17 (4 3/3 2/2 3) III 2 5 7 (1 2/1 1/1 1) 8 (1 2/1 2/1 1) 7 (1 1/1 2/1 1) 17 (4 3/3 2/2 3) IV 1 5 8 (1 2/1 2/1 1) 9 (1 2/1 3/1 1) 8 (1 1/2 2/1 1) 19 (4 3/4 2/3 3)

Male ( Figs 5 View FIGURE 5 , 6 View FIGURE 6 , 8 View FIGURE 8 B) (10 specimens measured).

Dorsal idiosoma ( Fig. 1 View FIGURE 1 ). Dorsal shield 973 ± 20 (940–1010) long, maximum width 825 ± 18 (805–850), ratio length/width 1.18 ± 0.03 (1.13–1.22); ornamentation, chaetotaxy, pores and pore-like structures as in female.

Ventral idiosoma ( Figs 5 View FIGURE 5 , 6 View FIGURE 6 C, 6D, 6E, 8B). Holoventral shield ( Figs 5 View FIGURE 5 , 8 View FIGURE 8 B) with anterior corners oblique, anterior margin weakly concave and bent upward as in female sternal shield, 11 pairs of setae; st1 (38) and anterior lyrifissures as in female; st2 (24) at level of posterior lyrifissures; st3 (24) at level of acetabula II; st4-st5 (24) at level of acetabula III, with st5 medially displaced; six pairs of ventri-anal setae as in female; three to five additional sternal setae and one small pore between st3 and st4; two typical porose areas near genital opening ( Figs 6 View FIGURE 6 C, 6D, 6E); intercoxal region fused with endopodal shields. Peritremes, peritrematal, exopodal and marginal shields, chaetotaxy and pores and pore-like structures distribution as in the female.

Gnathosoma ( Figs 2 View FIGURE 2 B, 2C, 6A, 6B). As in female, with following differences: epistome with apex widely rounded ( Fig. 6 View FIGURE 6 A); movable digit of chelicera with spoon-like process and only one large feather-like excrescence ( Fig. 6 View FIGURE 6 B). Spoon-like process with saw-like structures not discernible.

Legs. As in the female.

Notes. The original description of the holotype of Lobogynium sudhiri apparently shows some differences from European and Iranian specimens in details of the holoventral shield, palp and leg chaetotaxy. For example, on the palp femur of L. sudhiri as illustrated by Datta (1985) ( Fig. 2 View FIGURE 2 E), pl is a short, stout and spine-like seta, while in the examined specimens pl is longer, needle-like and weakly barbed ( Fig. 2 View FIGURE 2 B). Furthermore, on the palp genu ( Fig. 2 View FIGURE 2 E, Datta, 1985) al2 is a small spine-like seta, while in the examined specimens al2 is a long and needle-like seta ( Fig. 2 View FIGURE 2 B). Datta (1985) also reports one small spine-like seta on the telotarsus III ( Fig. 3 View FIGURE 3 H) and at the apex of telotarsus II ( Fig. 3 View FIGURE 3 G), but these setae are not present in the examined specimens.

These differences, which appear to be subtle and ambiguous, could be due to intraspecific variation or more likely attributed to inaccurate description and illustration of some characters. The shape and length of setae are difficult to observe when the setae are vertically orientated and it is not possible to examine them in other specimens. The original description of Lobogynium sudhiri also contains some discrepancies with figures and errors in captions, as well as some details of the leg chaetotaxy incorrectly or incompletely illustrated. This description reads in part as follows: "Gnathosoma with six pairs of deutosternal grooves with denticles, 4 pairs of setae, gs1 and gs2 long, gs3 short and lanceolate". Although this written description of the relative length of the hypostomal setae agrees with our observations, the figure of the gnathosoma by Datta (1985) ( Fig. 2 View FIGURE 2 F), shows setae hyp2 and hyp3 subequal in length and clearly shorter than hyp1. Moreover, the figure of the idiosomal venter by Datta (1985) ( Fig. 2 View FIGURE 2 B) shows at least six pairs of ventri-anal setae posterior to intercoxal region, instead of five setae as indicated by the same author ("ventrianal region with 5 pairs of setae") and as observed in our material. Datta (1985) reports for the basitarsus II at least six setae ( Fig. 3 View FIGURE 3 G), but in all species of the order Mesostigmata , basitarsi II-IV have only four setae. In the family Diplogyniidae , the number of setae on the genu is nine for leg II and IV, and eight for leg III, but according to illustrations by Datta (1985), genua II ( Figure 3 View FIGURE 3 L) and IV ( Figure 3 View FIGURE 3 K) have only seven and eight setae respectively. Finally, there are some errors in the captions: genu III is missing in Figure 3 View FIGURE 3 H; figure 3L is the illustration of the genu and not that of the femur; and Figure 3 View FIGURE 3 K represents a genu and a tibia and not a femur and a genu as reported.

It is particularly interesting to note the presence of two porose areas in the male genital area of L. sudhiri ( Figs 5 View FIGURE 5 , 6 View FIGURE 6 C, 6D, 6E), which were not described and illustrated in detail by Datta (1985). Similar structures have been illustrated from other diplogyniid species ( Trägårdh, 1950; Elsen, 1975; Seeman, 2007) and their presence only in the males suggests they are a secondary sexual character with the function of gland openings. Surprisingly, the porose areas are less differentiated in some Iranian specimens, in which a large central pore is more visible ( Fig. 6 View FIGURE 6 D). This feature makes the porose areas most similar to those illustrated by Datta (1985) and this is further evidence of conspecificity with Ophiocelaeno sudhiri .

European and Iranian specimens of Lobogynium sudhiri show another long and stout seta (d2) on the dorsal surface of the palpal femur ( Fig. 2 View FIGURE 2 B). Seta d2 was not illustrated by Datta (1985), but its putative insertion pore appears in the relative position ( Fig. 2 View FIGURE 2 E) indicating that this seta was simply detached in the holotype of L. sudhiri .

The strongly sclerotised antero-lateral circum-anal area ( Figs 3 View FIGURE 3 , 5 View FIGURE 5 , 8 View FIGURE 8 ) appears to be an autapomorphic feature of Lobogynium sudhiri , as this feature apparently is not present in other described diplogyniid species.

A small protuberance can be observed laterally near the base of the corniculi in specimens of both sexes. An additional unpaired ventral seta placed laterally at JV3 also was present only in some Iranian specimens.

Lobogynium sudhiri differs from the other two Lobogynium species by the shape of the metasternal shields, the chaetotaxy of the palp femur and the position of ventral setae in the opisthosomal region. In L. rotundatum and L. pascuum the metasternal shields are separate, while in L. sudhiri these shields are fused entirely along their medial margins to form a single plate ( Fig. 4 View FIGURE 4 E). The palp femur in L. sudhiri has two long stout setae (d1 and d2) and one spur-like seta (al) ( Fig. 2 View FIGURE 2 B), while in L. rotundatum and L. pascuum all setae on the palp femur are simple and needle-like. In Lobogynium sudhiri the ventri-anal setae JV2 and ZV2 are closer to each other and to the anal opening than in other two species of the genus ( Figs 3 View FIGURE 3 , 5 View FIGURE 5 ).

Detailed illustrations of the leg chaetotaxy in Diplogyniidae are very scarce in the literature. A study of this character in L. sudhiri and Paradiplogynium nahmani Seeman, 2007 , for which leg chaetotaxy has been described in detail, highlights some differences between these two species: on the femur I seta pd2 is present in L. sudhiri , but absent in P. nahmani , while seta pd3 is absent in L. sudhiri , but present in P. nahmani ( Fig. 2 View FIGURE 2 A; Fig. 6 View FIGURE 6 , Seeman, 2007); on the femur III seta pd2 is absent in L. sudhiri , but present in P. nahmani , while seta pl1 is present in L. sudhiri , but absent in P. nahmani ( Fig. 7 View FIGURE 7 B; Fig. 8 View FIGURE 8 , Seeman, 2007). However, in the absence of further comparative studies it is difficult to interpret the significance of these differences.