Alloptes (Sternalloptes) antarcticus, Han & Mironov & Kim & Min, 2021

Han, Yeong-Deok, Mironov, Sergey V., Kim, Jeong-Hoon & Min, Gi-Sik, 2021, Feather mites (Acariformes, Astigmata) from marine birds of the Barton Peninsula (King George Island, Antarctica), with descriptions of two new species, ZooKeys 1061, pp. 109-130 : 109

Alloptes (Sternalloptes) antarcticus sp. nov.

Type material.

Male holotype (NIBR No. NIBRIV0000887158), 3 males and 4 females paratypes (NIBR No. NIBRIV0000887159-NIBRIV0000887164) from Stercorarius maccormicki Saunders ( Charadriiformes , Stercorariidae ), Antarctica, King George Island, Barton Peninsula, 62°14'2"S, 58°46'20"W, 2 January 2016, coll. Han Y.-D.

Description.

Male (Figs 1 , 3A-E , 4A, B ; holotype, range for 3 paratypes in parentheses): idiosoma, length × width, 370 (340-365) × 200 (175-205). Length of hysterosoma 228 (213-243). Prodorsal shield (Figs 1A , 4A ): length 80 (78-80), width at posterior margin 114 (102-118), posterolateral corners truncate, posterior margin slightly concave. External scapular setae se situated on posterolateral extensions of prodorsal shield near their anterior margins. Hysteronotal shield: greatest length 255 (235-258), width at anterior margin 100 (98-108), anterior margin slightly concave, lateral margins without incisions at bases of setae d2 and fused ventrally with bases of epimerites IV. Length between prodorsal and hysteronotal shields along midline 31 (18-22). Dorsal setae c2 32 (33-36) long, shorter than trochanters III (Fig. 4C ). Subhumeral setae c3 narrowly lanceolate, 23 (19-23) × 2 (3). Posterior part of opisthosoma gradually expanded at posterior end, width at level of setae h2 50 (46-53). Length of interlobar septum 82 (80-86). Terminal lamella with three pairs of festoons; incision between inner pair narrow slit-like or inner festoons slightly overlapping. Setae h3 present, setae ps2 distinct. Setae h2 cylindrical, not expanded in medial part. Dorsal measurements: se: se 118 (96-106), c2: d2 55 (50-57), d2: ps1 165 (158-168). Bases of trochanters I, II flanked by narrow sclerotized bands connecting bases of corresponding epimerites (Fig. 1B ). Pregenital sclerites fused as a Y, their anterior ends connected to inner ends of epimerites IIIa, posterior end fused with paragenital arch. Coxal fields III and IV closed. Length of genital-anal field 163 (158-168). Genital arch: 17 (15-17) × 20 (19-20). Coxal setae 4b situated anterior to level of setae 3a. Setae 4a surrounded by sclerites of irregular form. Ventral measurements: 3a: 4b 10 (9-13), 4b: g 45 (43-43), 4b: 4a 63 (60-65), g: ps3 30 (31-35), ps3: ps1 110 (109-117), 4a: 4a 120 (110-112). Setae mG of genua I thin spine-like with acute apex, setae mG II shaped as thick spine with bluntly rounded apex. Legs IV 203 (193-203) long. Distal margin of tibia IV with small spine. Tarsus IV 54 (49-55) long, with claw-like apex; setae d and e small spine-like, seta e situated near tarsal apex, seta d at level of seta f, setae r and w in basal one-third of the segment (Fig. 3A-C ).

Female (Figs 2 , 4F, G , 4C ; range for 4 paratypes): idiosoma, length × width, 350-360 × 148-153 (Fig. 2A ). Hysterosoma 238-250 long. Prodorsal shield: shaped as in male, 80-83 × 85-90. Setae c2 10-14 long, shorter than trochanters III. Setae c3 lanceolate, 13-15 × 2-3. Hysteronotal shield: 233-238 × 60-62, anterior margin straight or slightly concave, surface without ornamentation. Setae h1 and e2 situated at same transverse level. Setae f2 and ps1 absent. Distance between prodorsal and hysteronotal shields along midline 23-33. Supranal concavity ovate, opened posteriorly, delimited from terminal cleft by short extensions. Opisthosomal lobes well developed, approximately as long as wide at base, terminal cleft as an inverted U, 24-30 long, 12-20 wide (Fig. 4C ). Anterior end of supranal concavity extending slightly beyond level of setae h2. Dorsal measurements: se: se 83-89, c2: d2 64-67, d2: e2 104-106, e2: h2 39-43, h2: h3 19-20, h2: h2 55-60, h3: h3 25-31. Bases of trochanters I, II flanked by narrow sclerotized bands connecting bases of corresponding epimerites (Fig. 2B ). Epimerites IVa barely distinct. Epigynum bow-shaped, 24-27 × 55-59. Legs IV with ambulacral discs reaching level of insertions of setae h2 (Figs 2 , 3F, G ).

Differential diagnosis.

Among 18 previously known species in the subgenus Alloptes Sternalloptes ( Kivganov and Mironov 1992; Mironov and Kivganov 1993; Kivganov 1996; Hernandes et al. 2017), the new species Alloptes (S.) antarcticus sp. nov. is most similar to A. (S.) catharacti Mironov, 1991 found on the same host, S. maccormicki from Mirny station (Queen Mary Land, Antarctica), in having setae c3 lanceolate and short (shorter that trochanters III), the pregenital sclerite fused into a Y connecting the tips of epimerites IIIa and the apex of the paragenital arch, and setae h2 not expanded ( Mironov 1991). Alloptes (S.) antarcticus sp. nov. differs from A. (S.) catharacti in having the following characteristics: in both sexes, the external scapular setae se are situated on the posterolateral extensions of the prodorsal shield; in males, the dorsal setae c2 (32-36) are approximately 1.5 times longer than setae c3 (19-23) and shorter than trochanters III (Fig. 4A, B ); in females, the terminal cleft is shorter (24-30 long), and the supranal concavity is open posteriorly into the terminal cleft (Fig. 4C ). In both sexes of A. (S.) catharacti , setae se are situated on the soft tegument near the anterior margin of the posterolateral extensions of the prodorsal shield; in males, the dorsal setae c2 (63-93) are 2-3 times longer than setae c3 (24-29) and exceed the length of trochanters III (Fig. 4D, E ); in females, the terminal cleft is longer (38-48), and the supranal concavity is separated from the terminal cleft ( Mironov 1991) (Fig. 4F ).

Remark.

The comparative material of A. (S.) catharacti used here to illustrate morphological differences was collected from the same host species, S. maccormicki , at Jangbogo station, Terra Nova Bay, Antarctica, in 2016, by Ji-Yong Lee.

Molecular data.

The COI sequences were obtained from two individuals and deposited in GenBank with accession numbers MZ489641 and MZ489642.

Etymology.

The specific name refers to the geographical range of the type host.

Figures

Figure 1. Alloptes (Sternalloptes) antarcticus sp. nov., male A dorsal view B ventral view.

Figure 2. Alloptes (Sternalloptes) antarcticus sp. nov., female A dorsal view B ventral view.

Figure 3. Alloptes (Sternalloptes) antarcticus sp. nov., details A opisthosoma of male, dorsal view B leg I of male C leg II of male D leg III of male E leg IV of male F leg III of female G leg IV of female.

Figure 4. Alloptes species A-C Alloptes (Sternalloptes) antarcticus sp. nov. D-F A. (S.) catharacti A, D prodorsal shield of males B, E humeral shield of males C, F opisthosomal lobes of females.