Constantinescu, Ioana Cristina ¹ ; Chișamera, Gabriel Bogdan ² ; Motoc, Rozalia ³ ; Gustafsson, Daniel R. ⁴ ; Zou, Fasheng ⁵ ; Wang, Zhengzhen ⁶ ; Grossi, Alexandra A. ⁷ ; Zhou, Wenyi ⁸ and Adam, Costică ⁹

¹✉ "Grigore Antipa" National Museum of Natural History, Sos. Kiseleff no.1, 011341 Bucharest, Romania.
²Institute of Biology – Bucharest, Romanian Academy, Splaiul Independenței 296, 060031 Bucharest, Romania.
³"Grigore Antipa" National Museum of Natural History, Sos. Kiseleff no.1, 011341 Bucharest, Romania.
⁴Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Library of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Sciences, 105 Xingang West Road, Haizhu District, Guangzhou, 510260, Guangdong Province, China.
⁵Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Library of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Sciences, 105 Xingang West Road, Haizhu District, Guangzhou, 510260, Guangdong Province, China.
⁶Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Library of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Sciences, 105 Xingang West Road, Haizhu District, Guangzhou, 510260, Guangdong Province, China.
⁷Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Library of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Sciences, 105 Xingang West Road, Haizhu District, Guangzhou, 510260, Guangdong Province, China.
⁸Department of Health and Environmental Sciences, Xi’an Jiaotong-Liverpool University, Suzhou, Jiangsu, China & Department of Biology, University of Florida, Gainesville, Florida, USA & Florida Museum of Natural History, University of Florida, Gainesville, Florida, USA.
⁹"Grigore Antipa" National Museum of Natural History, Sos. Kiseleff no.1, 011341 Bucharest, Romania.
¹⁰

2026 - Volume: 66 Issue: 2 pages: 552-578

ZooBank LSID: 5E3BEEB7-CFA8-49A1-853A-458725524EB1

Original research

Keywords

Abstract

Introduction

Feather mites (Astigmata: Analgoidea and Pterolichoidea) constitute one of the most diverse and widespread groups of avian ectosymbionts, inhabiting the plumage of nearly all extant bird species (Gaud and Atyeo 1996; Mironov and Proctor 2008). They are permanent symbionts, completing their entire life cycle—from egg to adult—strictly within the microhabitats provided by their hosts' feathers and exhibit a remarkable degree of host specificity.

Despite their large geographical distribution, the documented diversity of feather mites in China remained notably limited for decades. Evaluations by Wang and Fan (2010) and Constantinescu et al. (2019) highlighted this knowledge gap, recording only about 100 known species at the time. This figure represents a significant underestimation of the actual fauna of these mites, considering that China supports a rich ornithological diversity of over 1,500 bird species (Zeng 2023). Given the high host-specificity of these mites and the sheer variety of their hosts, we anticipate that a much higher level of mite diversity remains to be discovered and described.

This study aims to address the knowledge gap concerning feather mite fauna in southern China, by describing two new species of feather mites from the genera Dolichodectes and Trouessartia.

The feather mite genus Dolichodectes Park & Atyeo, 1971 (Analgoidea: Proctophyllodidae) is an easily recognisable, relatively non-specious taxon in the subfamily Pterodectinae, currently comprising thirteen species (Gaud and Mouchet 1957; Park and Atyeo 1971; Mironov and Fain 2003; Mironov et al. 2010, 2012, 2015; Mironov 2023, 2026; Constantinescu et al. 2018). It belongs to the Montesauria generic complex, which is characterized by the unusual position of the genital papillae in males. In mites of this complex, the genital papillae in males are typically strongly reduced and situated at the level of the genital arch—a trait that diverges from most other proctophyllodid taxa. This complex is primarily associated with Old World passerines and represents one of derived lineages of pterodectine mites (Mironov 2006, 2009). Species of Dolichodectes are readily identified by its markedly elongated idiosoma in both sexes. In males, the opisthosomal lobes are significantly elongated, usually 2-3 times longer than wide, and the ps3 setae are typically positioned posterior or posterolateral to the adanal suckers, resulting in the arrangement of ps3 and g setae in a longitudinal rectangle or a tall trapezoid. The genus is predominantly associated with the family of Old-World flycatchers Muscicapidae, however some species have also been recorded on hosts from other passerine families, Acrocephalidae, Passeridae, Phylloscopidae, Platysteiridae, Stenostiridae and Turdidae (Mironov et al. 2015; Constantinescu et al. 2018). A comprehensive updated checklist and species key were recently provided by Mironov (2023).

The feather mite genus Trouessartia Canestrini, 1899 (Analgoidea: Trouessartiidae) comprises 160 species associated predominantly with birds from the order Passeriformes. A world revision of this genus including 71 species was made by Santana (1976); other species were described in subsequent forty years by various authors, and can be found mentioned in almost all recent publications which refers to this genus (Mironov 1983, 2022; Gaud and Atyeo 1986, 1987; Mironov and Kopij 2000; Mironov and Galloway 2019; Mironov and Chandler 2020; Constantinescu et al. 2013; Hernandes 2014; Mironov and Dmitryukov 2025; Hernandes and Licarião 2025). Mironov (2022) provided an updated world checklist of Trouessartia and uniform diagnoses of 11 species groups currently recognized in the genus.

The new species of Trouessartia described herein cannot be referred to any of the 11 species groups previously established in the genus, because of having a specific combination of characters. However, in some features it is close to a grouping of Trouessartia species associated with Leiotrichidae, Pellorneidae and Alcippeidae (Constantinescu et al. 2016a, 2016b, 2021, 2023), which has not been formally circumscribed as a species group.

Materials and methods

The material examined in this study was collected from avian hosts in China during surveys of bird ectoparasites carried out by a team of researchers from Institute of Zoology, Guangdong Academy of Sciences (China) and ''Grigore Antipa″National Museum of Natural History (Romania) in March 2019 and December 2023. Specifically, specimens were obtained from the Mountain Bulbul, Ixos mcclellandii (Pycnonotidae), in Guangdong Province, and the Red-tailed Laughingthrush, Trochalopteron milnei (Leiothrichidae), in Yunnan Province. The birds were captured with mist-nets, identified and visually checked for the presence of mites; after collecting of mites, they were released back into the wild. Mite specimens were placed in tubes with 95% ethanol, and later, in the laboratory, were cleared in lactic acid and mounted on microscope slides in Hoyer's medium. Drawings were made using an Olympus CX21 microscope equipped with a camera lucida drawing device. Description of the new species of Dolichodectes follow the established standards for this genus and related pterodectine mites (Valim and Hernandes 2010; Mironov et al. 2010, 2012; Hernandes 2022, 2023). Measurement techniques for specific structures are based on comprehensive taxonomic studies of pterodectines (Mironov and González-Acuña 2011; Mironov and Chandler 2017; Mironov and Galloway 2021). Description of the new species of Trouessartia is given according to the standards proposed for mites of this genus in the recent taxonomic works (Mironov and González-Acuña 2013; Hernandes 2014, 2017, 2022; Mironov and Galloway 2019; Mironov and Chandler 2020; Mironov et al. 2021), and the measuring techniques of particular structures follow Mironov and González-Acuña (2013). General morphological terminology, along with idiosomal chaetotaxy, follows Gaud and Atyeo (1996), incorporating the corrections for coxal setation proposed by Norton (1998), and that of the legs chaetotaxy follows Grandjean (1939). All measurements are provided in micrometers (μm).

For examination with a Phenom Pro scanning electron microscope (Thermo Fisher Scientific) at the acceleration voltage of 10 kV, feather mites were rehydrated and then fixed in 3% glutaraldehyde in 0.1 M sodium cacodylate buffer (pH 7.4). The specimens were dehydrated through a graded ethanol series (30%, 50%, 70%, 80%, 90%, and 100%), transferred to mixed ethanol–hexamethyldisilazane (HMDS) solutions (3:1, 1:1, and 1:3), and finally placed in 100% HMDS (Han and Min 2019; Han et al. 2019). The samples were left 15 hours to allow chemical evaporation and complete drying. Specimens were mounted on aluminum stubs using conductive double-sided carbon adhesive tabs and sputter-coated with gold for 60 s (SEM Coating Unit E5100).

Identification of bird specimens was based on Arlott (2017), the scientific names and taxonomy of the birds follow the IOC World Bird List, v 15.1 (Gill et al. 2025). We give the full set of measurements for a holotype (male) and the range of measurements for all corresponding paratypes. All measurements are in micrometers (μm).

The type specimens of the new species are deposited in the Institute of Zoology, Guangdong Academy of Science, Guangzhou, China (IZGAS, previously the Guangdong Institute of Applied Biological Resources, GIABR) and in the Acarological Collection of the ''Grigore Antipa″National Museum of Natural History, Bucharest, Romania (MGAB). Specimens with the collection index GD-ACARI are in the IZGAS, and those with the accession collection index ANA are in MGAB.

Taxonomy

Family Proctophyllodidae Trouessart & Mégnin, 1884

Subfamily Pterodectinae Park & Atyeo, 1971

Genus Dolichodectes Park & Atyeo, 1971

Dolichodectes foliaceus Constantinescu sp. n

ZOOBANK: 9E05A2FE-75FD-415F-9888-740A155350FD

(Figures 1–8)

Type material

Holotype male, 12 male and 13 female paratypes from Ixos mcclellandii (Horsfield, 1940) (Pycnonotidae): CHINA, Guangdong Province, Dinghu District, Dinghushan National Nature Reserve, 22°09′34″N, 112°32′17″E, 17 March 2019; collector of all samples Costică Adam.

Depository — Male holotype (ANA2225), 9 male (ANA2226–2234) and 10 female (ANA2235–2244) paratypes, in MGAB collection; 3 male (GD-ACARI-66–68) and 3 female (GD-ACARI-69–71) paratypes, in IZGAS collection.

Description

Male — (holotype, range for 4 paratypes in parentheses) (Figures 1, 2, 5, 6). Idiosoma, length × width, 515 (525–550) × 163 (140–163), length of hysterosoma 365 (370–380). Prodorsal shield: entire, anterolateral extensions acute and not fused to epimerites Ia, lateral margins concave, posterior margin medially convex, posterior corners acute, surface with ovoid lacunae, length along midline 150 (153–158), width at posterior margin 125 (120–128) (Figure 1A, 6B). Setae ve represented by microsetae. Bases of scapular setae se separated by 55 (55–58). Scapular shields narrow, well developed dorsally. Humeral shields represented by small longitudinal sclerites, separated from epimerites III, not encompassing setae cp. Setae cp and c2 situated on soft tegument. Setae c3 lanceolate, 38 (33–43) × 12 (10–11). Hysteronotal shield: length from anterior margin to lobar apices 350 (370–375), width at anterior margin 100 (100–105), anterior margin straight, anterior corners rectangular, lateral margins with small longitudinal invaginations between setae e1 and e2, surface from anterior margin to level of setae e2 with round and ovate lacunae. Metapodosomal sclerites absent. Opisthosoma slightly attenuate from level of setae e2 to lobar apices. Opisthosomal lobes about 4 times longer than wide, posterior end of each lobe bluntly rounded, with concave posterior margins, bases of setae h2 on barely developed lateral extensions (Figures 1A, 2E, 6C, D). Setae h3 leaf-like, resembling linden leaves, 33 (32–35) long and 25 (25–27) wide, situated near to lobar apices. Terminal cleft shaped as narrow parallel-sided slit, lateral margins almost touching, length 90 (88–98). Supranal concavity ovoid, with heavily sclerotized border, distant from anterior end of terminal cleft. Setae f2 posterior from level of anterior end of terminal cleft; setae ps2 situated at same transverse level and mesal from them. Setae h1 slightly anterior from supranal concavity. Setae ps1 filiform, about 23 (23–25) long, situated at mid-distance between seta h2 and h3, and closer to outer margins of the lobes. Setae ps2 67 (67–84) long, extending beyond lobar apices. Distances between dorsal setae: c2:d2 118 (113–128), d2:e2 120 (110–125), e2:h2 65 (65–70), h2:h3 48 (48–53), d1:d2 68 (68–75), e1:e2 50 (50–58), h1:h2 48 (43–55), ps1:h3 25 (23–28), h2:h2 50 (50–55), h3:h3 25 (23–25).

Epimerites I fused into a Y, with a very short sternum, posterior end of sternum with transverse extensions connected to medial part of epimerites II (Figure 1B). Epimerites II long but not fused with corresponding epimerites IIa. Rudimentary sclerites rEpIIa present. Inner tips of epimerites IIIa with L-shaped bends directed laterally, inner margins of these epimerites with short projections directed backward. Coxal fields I closed, coxal fields II-IV almost closed. Coxal fields I, II without large sclerotized areas. Coxal fields IV with large sclerotized areas connecting epimerites IV and IVa. Genital arch of moderate size, 38 (37–38) long, 25 (25–28) wide; basal sclerite of genital apparatus U-shaped. Aedeagus 200 (198–208) long, extending beyond half of the lobes, at level of ps1 setae. Genital papillae well distinct, situated at midlevel of genital arch, arranged in transverse row. Pregenital apodeme shaped as an inverted Y-shaped sclerite, anterior branch of this apodeme not fused with epimerites IIIa, posterior branches of this apodeme, epimerites IVa, sclerotized areas of coxal fields IV and genital shields fused together to form almost complete sclerotized oval surrounding genital apparatus. Genital shields incorporated in this ovate sclerite with semi-ovate posterior ends, not fused to each other at midline of body. Setae 4b on soft tegument, posterior to setae 3a, setae 4a on posterior branches of pregenital apodeme, setae g on genital shields. Opisthoventral shields narrow, extended to the apices of the lobes, not fused to each other posterior to anal opening, with short acute extension bearing ps3 setae at level of adanal suckers and with long acute extension at level of anterior end of terminal cleft. Adanal suckers 18 (17–18) in diameter, corolla without denticles, surrounding membrane with radial striae. Setae ps3 on opisthoventral shield positioned laterally to adanal suckers, setae g and ps3 arranged in tall trapezoid. Distances between ventral setae: 4b:4a 67 (67–72), 4a:g 52 (57–62), g:ps3 62 (50–64), ps3:h3 102 (92–99), ps3:ps3 55 (52–57).

Legs I longer than legs II; femora I, II with long ventral crests; tarsus, tibia and genu I, tibia and genu II with dorsal longitudinal crest, other segments of these legs without processes (Figure 2A, B). Solenidion σ of genu I at midlength of this segment; genual setae cGI, cGII setiform, setae mGI, mGII thickened in basal part and with filiform apex. Setae sR of trochanters III present. Solenidion ω1 of tarsus II shorter than this segment; setae d of tarsi II, III half as long as corresponding setae f. Tarsus IV 25 (27–30) long, with apical claw-like process; seta d button-like, situated at midlength of this segment; seta e absent (Figure 2D). Solenidion φ of tibia IV extending to midlevel of ambulacral disc. Lengths of solenidia: ω1I 12 (10–13), ω1II 8 (8–10), φI 92 (85–94), φII 58 (50–58), φIII 33 (25–30), φIV 42 (38–45).

Female — (range for 5 paratypes) (Figures 3, 4, 7, 8). Idiosoma, length × width, 510–525 × 145–158, length of hysterosoma 360–390. Prodorsal shield: anterolateral extensions widely round and free from epimerites Ia, lateral margins shallowly concave at level of scapular setae, posterior corners pointed, posterior margin convex, length along midline 133–140, width at posterior margin 120–128, surface with ovoid lacunae, bigger in anterior half than in posterior one (Figure 3A, 8A). Setae ve represented by microsetae. Bases of setae se separated by 63–70. Scapular shields narrow. Humeral shields represented by amall longitudinal sclerites, separated from epimerites III. Setae cp and c2 situated on soft tegument. Setae c3 lanceolate, 30–33 × 8–10. Anterior and lobar parts of hysteronotal shields completely separated dorsally from each other by narrow transverse band of soft tegument. Anterior hysteronotal shield: roughly rectangular, slightly narrowed between d2 and e2 setae, anterior margin slightly convex, posterior margin convex, posterior corners pointed, greatest length 280–290, width at anterior margin 100–125, surface with numerous ovoid and circular lacunae. Length of lobar region 80–95, greatest width 88–118, anterior margin deeply concave. Terminal cleft narrow, with lateral margins almost parallel, 60–70 long, 8–10 wide in anterior part. Supranal concavity present, circular. Setae f2 present. Setae h1 near anterior margin of lobar shield. Setae h2 spindle-like, 63–67 long, 10–12 wide. Setae ps1 situated dorsally on opisthosomal lobes, closer to level of setae h3 than to h2. Setae h3 filiform, about 13–18 long, about 1/6-1/5 the length of lobar region. Distances between dorsal setae: c2:d2 123–128, d2:e2 93–103, e2:h2 60–63, h2:h3 58–63, d1:d2 53–63, e1:e2 33–38, h1:h2 18–20, h1:h1 20–33, h2:h2 60–63.

Epimerites I fused into a Y, with very short sternum (Figure 3B). Lateral parts of coxal fields I, II without sclerotized areas. Epimerites IVa present. Translobar apodemes of opisthosomal lobes wide, fused to each other anterior to terminal cleft. Greatest width of epigynum 70–85. Copulatory opening located ventrally, immediately posterior to anal opening. Primary spermaduct with enlargement in proximal part and bifurcation on a short portion near head of spermatheca, secondary spermaducts 23–28 long (Figure 4E). Distances between pseudanal setae: ps2:ps2 45–50, ps3:ps3 28–30, ps2:ps3 20–25.

Legs I slightly longer than legs II, femora I, II with long ventral crest, tibiae I-IV with dorsal longitudinal crest. Solenidion σ of genu I shorter than half-length of this segment and situated in its distal part. Genual setae cGI, cGII and mGI short filiform, setae mGI, mGII filiform with thickened basal part. Setae sR of trochanters III present. Setae d of tarsi II–IV much shorter than corresponding setae f. Solenidion φIV about 1/4 of corresponding tarsus (Figure 4D). Lengths of solenidia: ω1I 13–15, ω1II 10–13, φI 70–80, φII 43–55, φIII 25–30, φIV 6–8.

Remarks

The new species Dolichodectes foliaceus sp. n. possesses a distinct morphological character that clearly differentiate it within the genus: in males, the setae h3 are extremely short and wide, foliform, resembling linden leaves. The new species Dolichodectes foliaceus sp. n. is most close to D. gymnoris Mironov, Literák, Čapek & Koubek, 2010, described from the Russet-browed Bush-sparrow Gymnoris dentata (Passeridae) (Mironov et al. 2010), in having the following features in both sexes: anterolateral extensions of prodorsal shield not fused with epimerites Ia. In males of both species, the opisthosomal lobes are obtuse, terminal cleft has parallel-sided lateral margins, the supranal concavity is ovoid, the pregenital apodemes are fused in a median sclerite shaped as an inverted Y which anterior end is free and fused with epimerites IIIa, the coxal fields III are almost closed and the genital papillae are situated at midlevel of genital arch. The new species differs from D. gymnoris in having, in both sexes, the humeral shields present (vs. absent in D. gymnoris) and the ornamentation of dorsal shields with circular and ovate lacunae (vs. the prodorsal shield lacks ornamentation and the hysteronotal shield with transverse striae). The males of D. foliaceus sp. n. differ from D. gymnoris by the following features: the opisthosomal lobes are about 4 times longer than wide, the posterior margins of the lobes are concave, setae h3 are short foliform and resemble linden leaves, the coxal fields I are closed, the coxal fields II are almost closed, the rudimentary sclerites rEpIIa are present, the opisthoventral shields are not fused to each other, and the aedeagus extends beyond the level of adanal suckers. In males of D. gymnoris, the opisthosomal lobes are about 2 times longer than wide, the posterior margins of the lobes are straight, the h3 setae are narrowly lanceolate, the coxal fields I, II are open, the rudimentary sclerites rEpIIa are absent, the genital and opisthoventral shields are fused forning transverse bridge, and the aedeagus extends to the anterior margin of adanal suckers. The females of D. foliaceus sp. n. differ from D. gymnoris by the following features: the supranal concavity is present, the terminal cleft has lateral margins almost parallel, the translobar apodemes of opisthosomal lobes are fused with each other anterior to the terminal cleft. In females of D. gymnoris. the supranal concavity is absent, the terminal cleft has divergent lateral margins, the translobar apodemes of opisthosomal lobes are not fused to each other anterior to the terminal cleft.

Etymology

The specific epithet foliaceus (L., adjective meaning ''leaf-like″) refers to the characteristic shape of the terminal setae h3 in males, which are flattened and resemble small leaves.

Family Trouessartiidae Gaud, 1957

Genus Trouessartia Canestrini, 1899

Trouessartia durascutata Constantinescu sp. n

ZOOBANK: 42D1EF3F-2DB4-4AC8-A956-130AA680C3F2

(Figures 9–18)

Type material

Holotype male, 12 male and 14 female paratypes from Trochalopteron milnei David, 1874 (Passeriformes: Leiothrichidae): CHINA, Yunnan Province, Dehong Prefecture, Tongbiguan, Nanduhe, 24°38′25.0″N, 97°38′45.0″E, 11 December 2023, coll. D.R. Gustafsson, Z. Wang, A.A. Grossi and W. Zhou, bird ID: J4913.

Depository — Male holotype (ANA2183), 10 male (ANA2184–2193) and 7 female (ANA2194–2200) paratypes, in MGAB; 2 male (GD-ACARI-72–73) and 7 female (GD-ACARI-74–80) paratypes, in IZGAS.

Male — (holotype, range for 4 paratypes in parentheses) (Figs. 9–11, 15, 16): Length of idiosoma from anterior end to bases of setae h3 500 (475–490), greatest width at level of humeral shields 233 (208–230). Length of hysterosoma from sejugal furrow to bases of setae h3 365 (335–365). Prodorsal shield: lateral margins not fused with scapular shields, anterolateral extensions rounded, length along midline 168 (148–158), greatest width in posterior part 170 (150–160), posterior margin convex and with heavily sclerotized band, surface with few ovoid lacunae in central area of posterior part (Fig. 9, 16A). Internal scapular setae si spiculiform, 25 (17–25) long, separated by 65 (63–68); external scapular setae se separated by 118 (100–110). External vertical setae ve minute. Setae c2 on humeral shields, spiculiform, 38 (33–40) long. Setae c3 narrowly lanceolate, with rounded apex, 20 (17–22) long. Prohysteronotal and lobar shields connected, they delimited from each other by lateral incisions posterior to bases of setae e2, and small non-sclerotized medial area of ovate form. Prohysteronotal shield: length 213 (195–200), width at anterior margin 153 (140–150), lateral margins with shallow concavity at level of trochanters III, bottom of these concavities with heavily sclerotized C-shaped patch, anterior margin of this shield with heavily sclerotized band, median area with small ovoid lacunae. Dorsal setae d1, d2, e1 and e2 minute. Length of lobar shield excluding lamellae 123 (108–115). Opisthosoma attenuate posteriorly; opisthosomal lobes fused with each other along midline forming a sclerotized median septum, and only apical parts of lobes posterior to level of setae h2 separated by narrow terminal cleft. Length of terminal cleft from anterior end to apices of lamellae 50 (50–58), width in anterior part 8 (8–12). Terminal lamellae semi-ovate in shape, their lateral and posterior margins with 9–11 rounded denticles, length from bases of setae h3 to lamellar apices 30 (30–33). Setae h1 anterior to setae h2. Distances between dorsal setae: c2:d2 100 (93–113), d2:e2 105 (103–123), e2:h2 108 (90–100), h2:h3 25 (23–30), h2:h2 45 (45–50), h3:h3 38 (33–38), d1:d2 63 (55–68), e1:e2 43 (33–40).

Epimerites I free. Rudimentary sclerites rEpIIa small circular. Genital apparatus situated between levels of trochanters III and IV, epiandrum present, length including epiandrum and basal sclerite 50 (45–48), greatest width 20 (18–20) (Fig. 10). Setae g filiform, located far posterior from base of genital apparatus, with bases clearly separated, postgenital plaque present (Fig. 11E). Anterior and posterior genital papillae similar in size and equidistant from midline. Adanal apodemes heavily sclerotized, without lateral membranes, with longitudinal ridge-like apophyses. Translobar apodeme present. Adanal shields absent. Adanal suckers 18 (15–17) in diameter. Anterior ends of epimerites IIIa reaching level of setae 4b; epimerites IVa present, their anterior ends not reaching level of setae 4a. Setae 4b situated anterior to level of setae 3a, setae g situated slightly posterior to level of setae 4a. Distances between ventral setae: 4b:3a 50 (48–53), 4b:g 107 (100–108), g:ps3 65 (68–75), ps3:h3 109 (105–113).

Setae cG, mG of legs I, II filiform; setae sR of trochanters III short, narrowly lanceolate, with rounded apex, 17(15–17) long. Tarsus IV 38 (37–40) long, modified setae d barrel-shaped with discoid cap, setae e barrel-shaped with rounded apex, both setae situated subapically (Fig. 11D, 16D). Legs IV with ambulacral disc extending beyond level of apices of terminal lamellae. Length of solenidia: σ1I 38 (38–45), σII 10 (8–10), σIII 13 (10–15), φIV 55 (45–50).

Female — (Figs. 12–14, 17, 18, range for 5 paratypes): Length of idiosoma from anterior end to apices of lamellar lobar processes 525–550, greatest width 215–230. Length of hysterosoma from sejugal furrow to apices of lamellar lobar processes 380–405. Prodorsal shield: shaped as in the male, 153–163 in length, 158–165 in width, posterior margin with heavily sclerotized band, surface with few ovoid lacunae in central area of posterior part. Setae si spiculiform, 20–23 long, separated by 65–70, external scapular setae se separated by 105–113. Setae c2 on humeral shields, spiculiform, 33–42 long. Setae c3 narrowly lanceolate, with rounded apex, 17–20 in length. Hysteronotal shield: length from anterior margin to bases of setae h3 325–350, width at anterior margin 143–153, anterior and lateral margins with sclerotised bands, lateral margins with shallow concavity at level of trochanters III, bottom of these concavities with heavily sclerotized C-shaped patch, surface between d1 and e1 setae with small circular and ovoid lacunae and between e1 and h1 setae with big ovoid lacunae (Figs. 12, 17A). Dorsal setae d1, d2, e1 and e2 minute. Setae h1 lanceolate, 10–12 long, situated anteromesal to bases of setae h2, 23–27 from each lateral margin of hysteronotal shield. Setae ps1 positioned dorsally on opisthosomal lobes, equidistant from outer and inner margins of lobe, closer to bases of h3 than to bases of h2 setae. Distance from bases of setae h3 to membranous apices of lobes 25–33. Setae f2 and ps2 present. Supranal concavity closed and separated from terminal cleft. Terminal cleft as an inverted U, length 92–104, width of cleft at level of setae h3 28–33. Interlobar membrane very narrow, distance from free margin of membrane to membranous lobar apices 85–95. External copulatory tube present, minute, situated on margin of interlobar membrane. Spermatheca with collar, its margin with fringe of acute denticles; primary spermaduct not thickened; secondary spermaducts 22–30 long; with minute denticles (Fig. 14E); guides of copulatory tube absent. Distances between dorsal setae: c2:d2 105–108, d2:e2 110–120, e2:h2 70–75, h2:h3 55–65, h2:h2 80–88, h3:h3 53–63.

Epimerites I free. Epigynum 43–50 in length, 90–103 in width (Fig. 13). Epimerites IVa present.

Legs I–III as in the male. Setae sR of trochanters III narrowly lanceolate 15–17 long (Fig. 14C). Legs IV with ambulacral discs almost extending to level of setae h3. Length of solenidia: σ1I 38–45, σII 8–13, σIII 10–15, φIV 13–18.

Etymology

The specific epithet is a combination of the Latin roots durus (hard, tough) and scutatus (shield-bearing), adjective, gender feminine. It refers to the thickened and heavily sclerotized dorsal shields of this species, especially in females.

Remarks

Trouessartia durascutata sp. n. has morphological similarities to Trouessartia asiatica Constantinescu, 2023 described from the Rusty-capped Fulvetta, Schoeniparus dubius (Fam. Pellorneidae) (Constantinescu et al. 2023). In males, the terminal lamellae are semi-ovate in shape with rounded denticles on margins, the genital setae g are located far posterior from the base of genital apparatus and posterior to the level of setae 4a, the genital apparatus is narrow and almost parallel-sided; in females, the supranal concavity is heavily sclerotized, closed and separated from the terminal cleft.

Both sexes of T. durascutata sp. n. differ from T. asiatica by the ornamentation of dorsal shields. In males of the new species, both prodorsal and prohysteronotal shields bear ovoid lacunae (vs. ornamentation is missing in T. asiatica). In females of T. durascutata sp. n., the prodorsal shield bears ovoid lacunae and the hysteronotal shield has ornamentation along almost its entire length, while in females of the related species, the prodorsal shield does not have any ornamention, and the hysteronotal sheld bears ovoid lacunae only in the posterior half.

Males of T. durascutata sp. n. are clearly distinguished by the following features: the postgenital plaque is present, the genital setae g are filiform, the apophyses on adanal apodemes are present, the terminal lamellae have denticulate lateral margins, and the legs IV with ambulacral discs extend beyond the level of terminal lamella apices. In males of T. asiatica, the postgenital plaque is absent, setae g are enlarged in basal 2/3^rd, the apophyses of adanal apodemes are absent, the terminal lamellae have the lateral margins straight, and the legs IV with ambulacral discs extend to the level of setae h3. Females of the new species are clearly differentiated by the presence of small external copulatory tube, the spermatheca having a collar with fringe of small denticles (vs. external copulatory tube is absent and the spermatheca lacks a collar in T. asiatica).

The new species described herein cannot be included in any of 11 species groups that have been previously established in the genus Trouessartia, because of having a distinct combination of characters.

Acknowledgments

The present study was carried out in strict accordance with the Regulation for the Administration of Laboratory Animals (Decree No. 2, State Science and Technology Commission of the People's Republic of China, 14 November 1988). We obtained approval for the study from the Guangdong Institute of Zoology's (formerly Guangdong Institute of Applied Biological Resources) Administrative panel on Laboratory Animal Care. This study was supported by grant GIABR-GJRC201701 from the Introduction of Full-Time High-Level Talent Fund of the Institute of Zoology, Guangdong Academy of Sciences, grant 2019QN01N968 from the Pearl River Talent Recruitment Program of Guangdong Province, grant QN20200130012 from the Foreign Young Talent Plan, and grant 31961123003 from the National Natural Science Foundation of China. Gabriel Bogdan Chișamera was funded by project no. RO1567-IBB09/2026 from the Institute of Biology Bucharest of Romanian Academy.

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