Ingrassia chionis, 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

Ingrassia chionis sp. nov.

Type material.

Male holotype (NIBR No. NIBRIV0000887181), 2 males and 3 females paratypes (NIBR No. NIBRIV0000887182-NIBRIV0000887186) from Chionis albus (Gmelin) ( Charadriiformes , Chionidae ), Antarctica, King George Island, Barton Peninsula, 62°14'13"S, 58°46'33"W, 11 January 2016, coll. by Han Y.-D.

Description.

Male (Figs 5 , 7A-D ; holotype, range for 2 paratypes in parentheses): length of idiosoma from anterior end to bases of setae h3 350 (350-355), greatest width 220 (230-240), length of hysterosoma 175 (173-175). Prodorsal shield: narrow longitudinal plate with almost parallel lateral margins and acute posterior end extending beyond level of scapular setae se; length along midline 113 (118), greatest width 28 (27-29); anterior end with short longitudinal ridge about 1/8th the length of shield (Fig. 5A ). Setae se and si at same transverse level, bases of setae se situated on teardrop-shaped sclerites and separated by 69 (73-77). Scapular shields wide, inner margins slightly convex, without suprategumental extensions. Hysteronotal shield: anterior margin convex, length of shield from anterior end to bases of setae h3 213 (205-210). Setae c2 and d2 represented by macrosetae, 150 (150-150) and 110 (95-110) long, respectively; both pairs approximately 1.5 time shorter than humeral macrosetae cp. Opisthosomal lobes slightly longer than wide at base. Supranal concavity ovate, poorly outlined, separated from terminal cleft. Terminal cleft semi-ovate in shape, slightly narrowed anteriorly; length of terminal cleft from anterior end to bases of setae h3 63 (58-62), greatest width 40 (41-42). Terminal membranous extensions on lobar apices short and widely rounded, length from bases of setae h3 to apices of terminal extensions 20 (18-19), width of extensions at base 32 (27-28), length of incision between extensions 22 (19-20). Setae ps1 situated approximately at level of setae h2. Distance between dorsal setae: c2: c2 183 (180-188), c2: d2 33 (37-38), d2: e2 52 (50-53), e2: h3 88 (83-84), h3: h3 59 (55-57), ps1: ps1 39 (36-37).

Sternum about half as long as total length of epimerites I (Fig. 5B ). Anterior ends of epimerites IIIa free, widely separated from each other. Setae 4b situated on anterior ends of epimerites IIIa and almost extending to mid-length of opisthosomal lobes. Pregenital apodeme (epiandrum) small bow-shaped, 10 (7-9) long, 35 (32-38) wide. Genital apparatus 13 (10-12) long and 27 (27-28) wide. Setae g situated on small genital shields. Adanal shields triangular, situated anterolateral to setae ps3. Epimerites IVa long, almost completely enclosing coxal fields IV. Central part of coxal fields IV not sclerotized. Diameter of adanal suckers 19 (19-20). Distance between ventral setae: 4b: 4b 33 (35-36), 4b: 3a 24 (27-29), 4b: g 41 (42-43), g: ps3 29 (32-33), ps3: h3 97 (93-95).

Tarsi I, II each with short apicodorsal extension. Tibiae I, II with well-developed ventral spine-like processes (Fig. 7A, B ). Seta s of tibia II spiculiform. Femorogenu II with thick spine-like retrograde apophysis. Tibia III with small angular apical extension bearing base of solenidion φ. Length of tarsus III 81 (78-79). Tarsus IV with finger-like apical extension; modified setae d, e short spiculiform, seta e situated on tarsal apex, seta d subapical (Fig. 7C ). Legs IV excluding pretarsus 55 (51-58) long, with tarsus and distal half of genu extending beyond level of lobar apices (bases of setae h3) (Figs 5 , 7D ).

Female (Figs 6 , 7E, F ; range for 3 paratypes): length of idiosoma 400-435, greatest width 225-250, length of hysterosoma 220-238. Prodorsal shield: shaped approximately as in male, length 118-123, greatest width 30-33, anterior end with short longitudinal ridge about 1/8th the length of shield (Fig. 6A ). Setae se and si at same transverse level; bases of setae se situated on teardrop-shaped sclerites and separated by 75-82. Scapular shields wide, with smooth inner margin. Humeral shields well developed, without anteromesal extensions. Setae c3 short, slightly longer than trochanters III. Hysteronotal shield: large longitudinal plate occupying median part of hysterosoma; anterior part slightly widened; anterior margin right-angular, extending to or beyond level of setae c2; lateral margins unevenly sinuous; posterior margin truncate or slightly concave, extending to level of setae e2; greatest length 158-168, greatest width 85-93. Setae c2, d2, and e2 represented by macrosetae, 139-151, 112-131 and 81-93 long, respectively. Setae d1, d2, and e1 situated on hysteronotal shield, setae c2, e2 situated on striated tegument. Distance between dorsal setae: c2: d2 63-73, d2: e2 84-87, e2: h3 82 87, h3: h3 52-70.

Sternum about half as long as epimerites I. Epigynum thick and is bow-shaped, 13-22 long, 58-64 wide, with tips bearing bases of setae 4b. Apodemes of oviporus long, their posterior ends long and narrow, encompassing bases of setae 4a (Fig. 6B ). Setae 4b, g, 3a, and 4a short, not exceeding length of femorogenua III, IV. Setae h3 approximately two-thirds the length of setae h2.

Legs I, II as in the male. Legs IV with tarsus extending beyond posterior end of opisthosoma. Tarsi III, IV without apical spines, length of tarsi III, IV 60-61 and 72-74, respectively. Setae sR III subequal to combined length of corresponding femur, genu, and tibia. Seta w of tarsus III and setae r, w of tarsus IV spiculiform (Figs 6 , 7 ).

Differential diagnosis.

The new species Ingrassia chionis sp. nov. belongs to a group of species associated with the Charadriiformes and is characterized by a retrograde spine-like apophysis on femorogenu II in both sexes ( Gaud 1972; Vasyukova and Mironov 1991). Among this species grouping, the new species is most similar to I. tringae Vitzthum, 1922 (= I. minuta Gaud, 1972) described from Calidris minuta (Leisler) ( Scolopacidae ) in having the following features: in males of both species, the opisthosomal lobes are relatively short, equal to or slightly longer than wide at the bases, and the supranal concavity is completely separated from the terminal cleft; in females, the hysteronotal shield is shaped as a large longitudinal plate occupying the median area of the hysterosoma. Ingrassia chionis is distinguished from I. tringae by the following features: in both sexes, the prodorsal shield is narrow, parallel-sided, with the width about one-third the distance between setae se, and the posterior end of this shield is tapering; in males, the terminal cleft is semi-ovate, narrowed only in the anterior end, and tibia III bears a small apical spine of rectangular shape; in females, the anterior margin of the hysteronotal shield is right-angled and extends to the level of setae c2, and the posterior margin of this shield is truncate and extends to the level of setae e2. In both sexes of I. tringae , the prodorsal shield is a longitudinal plate widened posteriorly, with its greatest width equal to or larger than the halfway between setae se, and the posterior margin is widely rounded; in males, the anterior half of the terminal cleft is strongly narrowed, and tibia III bears a pointed apical spine; in females, the anterior margin of the hysteronotal shield is semi-ovate and does not extend to the level of setae c2, and the posterior margin of this shield is concave and extends beyond the level of setae e2.

Molecular data.

The COI sequences were obtained from two individuals and deposited in GenBank with accession numbers MZ489649 and MZ489650.

Etymology.

The specific name is taken from the generic name of the type host and is a noun in apposition.

Figures

Figure 5. Ingrassia chionis sp. nov., male A dorsal view B ventral view.

Figure 6. Ingrassia chionis sp. nov., female A dorsal view B ventral view.

Figure 7. Ingrassia chionis sp. nov., legs A tibia and tarsus I of male B tibia and tarsus II of male C tibia and tarsus III of male D tibia and tarsus IV of male E tibia and tarsus III of female F tibia and tarsus IV of female.