Research Article |
Corresponding author: Jenő Kontschán ( jkontschan@gmail.com ) Academic editor: Vladimir Pesic
© 2025 Jenő Kontschán, Sergey G. Ermilov.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Kontschán J, Ermilov SG (2025) A new remarkable representative of Uropodina mites from Seychelles (Acari, Mesostigmata, Trematuridae). ZooKeys 1229: 289-296. https://doi.org/10.3897/zookeys.1229.142822
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A new genus, Trematirunella gen. nov. (Mesostigmata: Uropodina: Trematuridae), with Trematirunella seychellia sp. nov. as its type species, is described, based on a female, males, and deutonymphs collected in soil samples from the Seychelle Islands. The new genus belongs to the family Trematuridae based on the shape of the corniculi, gnathosomal setae, tritosternum and chelicerae. Members of the new genus bear a preanal suture on the ventral shield, two pairs or more pairs of wide, robust and sword-like setae on the caudal part of the dorsal shield, very dense setation on the caudal area of the marginal shield and an incision on the anterior part of the dorsal shield. These characters are missing in the other genera of Trematuridae. Two previously described species (Trichouropoda lagunae Hirmatsu & Hirschmann, 1988 and Trichouropoda palawanensis Hirschmann & Hirmatsu, 1990) from the Philippines are transferred to the new genus, as Trematirunella lagunae (Hirmatsu & Hirschmann, 1988), comb. nov. and Trematirunella palawanensis (Hirschmann & Hirmatsu, 1990), comb. nov. The new species differs from its congeners in the sculptural pattern of the female genital shield and in the shape of the robust and sword-like setae on the caudal area of the dorsal shield.
Acari, new combination, new genus, new species, South-East Asia, taxonomy, trematurid mite
Nabuo Hiramatsu and Werner Hirschmann (1988) described a new, unusual Uropodina species (Trichouropoda lagunae Hiramatsu & Hirschmann, 1988) from the Philippines and placed it into the large catch-all genus Trichouropoda within Hirschmann’s specific systems in the Trichouropoda elegans-group. Two years later,
During the last decade, the first author spent several weeks in the Natural History Museum of Geneva to study the diversity of tropical Uropodina mites. Among their soil samples, an unusual trematurid mite species was found from the Seychelles, which differs from the other known genera in several unusual characters.
Specimens investigated were cleared in lactic acid for a week and afterwards were investigated with a Leica 1000 compound microscope with a drawing tube. Photographs were taken with a Keyence 5000 digital microscope. Specimens examined are stored in 70% ethanol and deposited in the Natural History Museum, Geneva (
Trematurini Berlese, 1917: 9.
Idiosoma oval, colour reddish-brown or yellowish-brown. Female genital shield scutiform usually with anterior process. Inner margin of marginal shield usually undulate. Corniculi with some (1–4) teeth, internal malae smooth, gnathosmal setae h1 smooth and often situated on small protuberance, h2–h4 pilose. Base of tritosternum vase-like, with or without lateral spines, tritosternal laciniae laterally pilose, movable digit of chelicerae as long as fixed digit, robust, with 3–5 teeth on both digits. Internal sclerotized node of chelicerae present.
Trematura Berlese, 1917: 12, by monotypy.
Trematurid mites. Idiosoma oval, posteriorly peaked or rounded. Dorsal shield with numerous long and apically pilose or shorter and smooth setae, two or more pairs of setae on caudal area of dorsal shield wide, robust and sword-like. Very dense setation situated on caudal area of marginal shield and an incision visible on anterior part of marginal shield. Ventral shield with preanal suture. Dorsal and ventral idiosoma covered by oval pits. Pedofossae weakly developed.
Trematirunella seychellia sp. nov.
The name of the new genus refers to the family name (Trematuridae).
Feminine.
The new genus differs from the other trematurid genera in the presence of two or more pairs of wide, robust and sword-like setae on the caudal part of the dorsal shield, the very dense setation on the caudal area of the marginal shield and an incision on the anterior part of the marginal shield, which are all missing in the other trematurid genera.
Trichouropoda lagunae Hiramatsu & Hirschmann, 1988: 194.
Philippines (
Trichouropoda palawanensis Hirschmann & Hiramatsu, 1990: 76–81.
Philippines (
Holotype. • Female. Seychelles, Praslin, 4°20'12"S, 55°44'8"E soil and decaying wood, 27 July 1982, C. Vaucher coll. Paratypes. Ten males and two deutonymphs. Locality and date same as in holotype.
Posterior margin of idiosoma rounded. Dorsal setae apically serrate. Setae in row J long, reaching basis of next setae. Surface of female genital shield without sculptural pattern. Ventral setae smooth and long.
Female (N = 1). Length of idiosoma 635, width at level of coxae IV 462, colour reddish-brown. Shape of idiosoma oval, posterior margin rounded.
Dorsal idiosoma
(Figs
Ventral idiosoma
(Fig.
Trematirunella seychellia gen. nov., sp. nov., holotype, female A dorsal setae and sculptural pattern B marginal setae C tritosternum D ventral view of gnathosoma E epistome F lateral view of chelicera G leg I, ventral view H leg II, ventral view I leg III, ventral view J leg IV, ventral view K intercoxal area of male paratype.
Gnathosoma
(Fig.
Legs
(Fig.
Male (N = 10). Body 630–637 long and 450–460 wide.
Dorsal idiosoma. As in female.
Ventral idiosoma
(Figs
Other characters as in female.
Deutonymph (N = 2). Idiosoma 450–455 long and 346–350 wide.
Dorsal idiosoma
(Fig.
Ventral idiosoma
(Fig.
Protonymph and larvae unknown.
The name of the new species refers to the islands, where the species was collected.
The most important differences among the known Trematirunella species are summarized in Table
T. lagunae | T. palawanensis | T. seychellia | |
---|---|---|---|
Caudal part of idiosoma | rounded | peaked | rounded |
Shape of dorsal setae | smooth | serrate | serrate |
Length of dorsal setae | shorter than distance between two setae | longer than distance between two setae | longer distance between two setae |
Surface of genital shield | with oval pits | with oval pits | smooth |
Length of st1 and st2 | two times shorter than st3 | two times shorter than st3 | as long as st3 |
Trematirunella species have been reported only from the Philippines and the Seychelles. The distance between the two known localities is considerable. Still, there is no information about the occurrence of the members of this genus in some of the most intensively studied countries (like Malaysia, Indonesia, and Thailand) (see
We are very grateful to Dr Peter Schwendinger (MHNG) for his kind hospitality during the first author’s visit to Geneva and to the collector of the soil samples in Seychelles Islands. We are also grateful for Dr Jason Dunlop for his linguistic corrections.
The authors have declared that no competing interests exist.
No ethical statement was reported.
No funding was reported.
All authors have contributed equally.
Jenő Kontschán https://orcid.org/0000-0001-8274-4238
Sergey G. Ermilov https://orcid.org/0000-0002-0913-131X
All of the data that support the findings of this study are available in the main text.