Phyllochaeta limosae, Han & Mironov & Min, 2022

Han, Yeong-Deok, Mironov, Sergey V. & Min, Gi-Sik, 2022, Two new species of feather mites (Acariformes, Astigmata) from the black-tailed godwit, Limosa limosa (Charadriiformes, Scolopacidae), in Korea, ZooKeys 1088, pp. 81-97 : 81

Phyllochaeta limosae sp. nov.

Type material.

Male holotype (NIBR no. NIBRIV0000895974), 1 male and 2 female paratypes (NIBR no. NIBRIV0000895975-NIBRIV0000895977) from the quills of flight feathers on wings of Limosa limosa ( Charadriiformes , Scolopacidae ), Korea, Chungcheongnam-do, Seosan-si, 37°0'12"N, 126°24'5"E, 6 July 2012, collected by Han Y.-D.

Description.

Male (Figs 5 , 7A-D ; holotype, measurements for 1 paratype in parentheses). Length of idiosoma from anterior end to bases of setae h3 560 (555), greatest width 260 (245), length of hysterosoma 410 (390). Prodorsal shield: entire, with posterior margin straight; length along midline 157 (155), greatest width 195 (195), distance between setae se 94 (93); surface without ornamentation, anterior part with a pair of grooves flanking narrow longitudinal rectangle (Fig. 5A ). Humeral shields well developed. Hysteronotal shield: anterior margin straight, length of shield from anterior end to bases of setae h3 390 (390), greatest width 200 (187), surface without ornamentation. Lateral sclerites fused with hysteronotal shield posterior to bases of setae e2. Setae c2, d2, and e2 represented by macrosetae, 150 (160), 440 (430), and 240 (260) long, respectively. Setae e1 situated posterior to setae e2, approximately at level of anterior end of terminal cleft. Opisthosomal lobes long, shovel-shaped, with distinctly enlarged distal parts, and with spine like dorsal process at bases of setae h1; greatest width at level of setae f2 50 (49). Terminal cleft large ovate, length of cleft from anterior end to bases of setae h3 138 (140), greatest width 81 (82), length-to-width ratio 1.7; ventral C-shaped sclerotized band at anterior end of the cleft with small median protuberance. Terminal membranes with 15 or 16 finger-like denticles along medioterminal margin. Setae ps1 lanceolate, 69 (68) × 8 (8), situated slightly posterior to level of setae h2. Setae h1 spiculiform, situated posterior to setae ps1. Distance between dorsal setae: c2: d2 147 (145), d2: e2 81 (83), e2: h3 142 (145), h3: h3 107 (100).

Sternum with terminal sclerotized plate shaped as a narrow triangle. Coxal fields II almost completely sclerotized, posterior tips of epimerites II with small heavily sclerotized ovate plates (Fig. 5B ). Pregenital apodemes shaped as an inverted L, their anterior ends connected by poorly sclerotized transverse bridge. Paragenital sclerites large, with enlarged anterior parts, not fused anteriorly. Base of genital apparatus at midlevel of trochanters III, genital arch 39 (37) long and 30 (28) wide, aedeagus 15 (13) long. Setae g situated on anterior ends of paragenital apodemes, approximately at level of setae 3a and c3. Setae 4a and 4b situated on same transverse level. Diameter of adanal suckers 24 (23), corolla with 16 or 17 round denticles. Adanal shields represented by small oblique sclerites situated anterior to setae ps3. Opisthoventral shields large triangular, fused anteriorly with posterior ends of paragenital sclerites. Distance between ventral setae: 4b: 3a 44 (40), g: 4b 46 (48), g: 4a 47 (50), 4a: ps3 92 (85).

Setae cG of genua I and II spiniform. Tarsi III and IV with small apicoventral spines between bases of setae s and r. Legs IV with ambulacral discs almost extending to level opisthosomal lobe apices. Setae d and e of tarsi IV spine-like, situated on distal end of tarsus, solenidion φ of tibia IV extending to proximal margin of ambulacral disc (Fig. 7A-D ).

Female (Figs 6 , 7E, F ; range for 2 paratypes). Length of idiosoma 475-485, greatest width 195-210, length of hysterosoma 340-345. Prodorsal shield: shaped approximately as in male, length 132-135, greatest width 182-197, distance between setae se 98-101; anterior part with a pair of groves flanking narrow longitudinal trapezoid (Fig. 6A ). Hysteronotal shield: entire, greatest length 325-340, greatest width 180-195, surface with faint longitudinal striation in posterior one-third. Anterior ends of lateral sclerites adjacent to hysteronotal shield, posterior parts of these sclerites gradually turned onto ventral side of hysterosoma. Lateral dorsal setae c2 short, filiform, 50-52 in length. Setae d2 and e2 represented by macrosetae, 280-290 and 305-320 long, respectively; setae f2 large spiculiform, 73-76 long. Distance between dorsal setae: c2: d2 130-137, d2: e2 102-105, e2: h3 80-85, h2: h2 76-80, h3: h3 54-59.

Epimerites I and II with narrow sclerotized areas, posterior end of sternum with triangular sclerotized plate. Epigynum small, roughly semicircular, 16-18 long, 27-28 wide. Setae g situated posterior to level of setae 3a and genital papillae. Setae ad short, 7-12 in length. Setae ps2 and ps3 filiform, 80-82, and 65-72 long, respectively.

Structure and setation of legs I and II as in males. Solenidion φ of leg I approximately as long as this leg. Setae cG of genua I and II blade-shaped. Tarsi III and IV without ventral blunt-angular extension. Solenidion φ of tibia IV slightly shorter than corresponding tarsus (Fig. 7E, F ).

Differential diagnosis.

The genus Phyllochaeta currently comprises 15 species known to infest birds of the genera Actitis , Arenaria , Calidris , Charadrius , Limnodromus , Prosobonia , and Rostratula ( Charadriiformes , Scolopacidae ) ( Dabert 2003). The newly described species Phyllochaeta limosae sp. nov., discovered here for the first time from Limosa limosa , and is most similar to Phyllochaeta secunda Dabert, 2003 described from the short-billed dowitcher, Limnodromus griseus (Gmelin, 1798) ( Scolopacidae ), with respect to the following features: in males of both species, ornamentation of the hysteronotal shield is absent, the opisthosomal lobes are shovel-shaped with distinctly enlarged distal parts, the terminal membranes have numerous finger-like denticles along the medioterminal margin, ventral apophyses of legs I and II are absent, and genual setae cG I and cG II are spine-like; in females, dorsal setae e1 are situated closer to the level of hysteronotal gland openings gl than to setae e2. Phyllochaeta limosae sp. nov. differs from P. secunda in the following characteristics: in males, the terminal cleft is semi-ovoid with a length-to-width ratio of 1.7, the terminal membranes have 15 or 16 finger-shaped denticles, the anterolateral extensions of the prodorsal shield are pointed, the hysteronotal shield is uniformly sclerotized, the tarsi of leg III and IV have blunt-angular ventral extensions, and setae 4a and 4b are approximately situated at the same transverse level; in females, the hysteronotal shield bears faint longitudinal striations in the posterior third and lacks any lacunae, and setae c1 are situated posterior to the level of setae c2. In males of P. secunda , the terminal cleft is distinctly wider (length/width ratio about 1.0), terminal membranes have 9 or 10 finger-shaped denticles, anterolateral extensions of the prodorsal shield are widely rounded, the hysteronotal shield has a pair of longitudinal heavily sclerotized bands near the terminal cleft, ventral apophyses of tarsi III, IV are hooked, and setae 4a are situated posterior to the level of setae 4b; in females, the hysteronotal shield is monotonously punctate and has a pair of ovate lacunae at the level of setae e2, and setae c1 and c2 are approximately at the same transverse level.

Remark.

The origin of Phyllochaeta limosae sp. nov. on Limosa limosa is enigmatic and disputable. Godwits ( Limosinae , Limosa ) and curlews ( Numeniinae , Numenius ) forming most basal lineages within Scolopacidae were previously known to bear only syringobiids of the genus Limosilichus Vasyukova & Mironov, 1986. This genus is apparently restricted to godwits and curlews, and most its species are monoxenous ( Vasyukova and Mironov 1990, 1991; Dabert 2003). While the genus Phyllochaeta currently including 15 species is widely distributed on waders of the tribes Arenariini , Tringini , and Scolopacini ( Scolopacinae ). Two species, P. secunda and P. gracilis Vasyukova & Mironov, 1986, which are close to P. limosae sp. nov., are specific to dowitchers Limnodromus griseus and L. scolopaceus (Say, 1823), respectively. Therefore, it is most reasonable to hypothesize that the ancestor of P. limosae sp. nov. had been transferred to the black-tailed godwit from some dowitchers.

Etymology.

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

Figures

Figure 5. Phyllochaeta limosae sp. nov., male A dorsal view B ventral view.

Figure 6. Phyllochaeta limosae sp. nov., female A dorsal view B ventral view.

Figure 7. Phyllochaeta limosae sp. nov., legs A genu, tibia and tarsus I of male B genu, 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.