Current taxonomical and faunistical state of the subgenus Pocsia Mahunka, 1983 (Acari, Oribatida, Euphthiracaridae) with description of a new species

Abstract

One new species of oribatid mites Euphthiracarus (Pocsia) parakunstin. sp. is described from Tanzania. The present state of knowledge of the 17 species of the subgenus Pocsia known in the world is outlined. A key for identification of all Pocsia species is included.

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Keywords::

• moss mites
• ptyctimous
• subgenus Pocsia
• new species
• key

Introduction

Ptyctimous mites characterized by ptychoidy, an ability of folding the aspidosoma under the opisthosoma to protect their appendages, are a rather speciose group of oribatid mites. Among the numerous species of Euphthiracaroidea, nearly 90 belong to the genus Euphthiracarus Ewing, 1917, and the majority to the subgenus Euphthiracarus. Mahunka (1983) created the genus Pocsia closely related to Euphthiracarus, and Niedbała (1998) reduced Pocsia to subgeneric status. Pocsia species are difficult to identify because of relatively few morphological characters and rather small morphological differences.

In this paper, one new species of Pocsia is described and the present state of knowledge of all the species of the subgenus is reported. Moreover, a key for identification of all Euphthiracarus (Pocsia) species is proposed.

Material and methods

I received a rich material of ptyctimous mites from Tanzania through the courtesy of Dr J. Stary, Institute of Soil Biology, České Budějovice. I found one new species of the subgenus Pocsia among other numerous species of ptyctimous mites.

The types are partly deposited at the Department of Animal Taxonomy and Ecology, Poznań, Poland (DATE) and partly at the Institute of Soil Biology BC ASCR, České Budějovice, Czech Republic (ISB), as well as at the Natural History Museum, Geneva, Switzerland (NHMG).

Procedures for the species identification and terminology generally follow Niedbała (2000).

Taxonomic account

Family Euphthiracaridae Jacot, 1930

Genus Euphthiracarus Ewing, 1917

Diagnosis

Prodorsum. Bothridial squamae situated below the bothridia; posterior median apodeme present, prodorsal setae in median position. Notogaster with 14 pairs of setae, terminal fissure, one pair of openings of lateral opisthosomal glands and five pairs of lyrifissures present. Ventral region with two, median and posterior, interlocking triangles.

Subgenus Pocsia Mahunka, 1983

Diagnosis

Prodorsum with rostral setae arising far posteriorly between the lamellar ones. Between genitoaggenital and anoadanal plates, well-developed suture is situated.

Euphthiracarus (Pocsia) parakunsti n. sp.

(Figure 1A–F)

Figure 1 Euphthiracarus (Pocsia) parakunstin. sp. (holotype). (A) Prodorsum, lateral view; (B) prodorsum, dorsal view; (C) opisthosoma, lateral view; (D) mentum of subcapitulum; (E) paraxial fragment of genitoaggenital plates; (F) genitoaggenital and anoadanal plates.

Material examined

Holotype and two paratypes (in DATE): TAN-007, Tanzania, Nguru Mts., Turiani, 06°06′24″S, 37°31′48″E, 1236 m asl, deciduous forest on a steep slope, litter sifting 05, 3.XI.2010, leg. V. Grebennikov; one paratype (in ISB): TAN-006, Tanzania, Nguru Mts., Turiani, 06°06′24″ S, 37°31′48″E, 1236 m asl, deciduous forest on a steep slope, litter sifting 07, 5.XI.2010, leg. V. Grebennikov; six paratypes (in DATE): TAN-009, Tanzania, Nguru Mts., Turiani, 06°04′29″S, 37°32′19″E, 1277 m asl, deciduous forest on a steep slope, litter sifting 06, 4.XI.2010, leg. V. Grebennikov; one paratype (in ISB): TAN-014, Tanzania, Uluguru Mts., Bunduki village, 07°01′06″S, 37°39′45″E, 1569 m asl, mid-altitude afromountain deciduous forest, litter sifting 27, 26.XI.2010, leg. V. Grebennikov; three paratypes (in NHMG): TAN-017, Tanzania, Uluguru Mts., Bunduki village, 07°00′15″S, 37°37′50″E, 1848 m asl, mid-altitude afromountaine deciduous forest, litter sifting 24, 24.XI.2010, leg. V. Grebennikov.

Other material (in DATE): 14 specimens, TAN-008, Tanzania, Nguru Mts., Turiani, 06°06′24″S, 37°33′26″E, 677 m, deciduous forest on a steep slope, litter sifting 02, 30.X. 2010, leg. V. Grebennikov; three specimens, TAN-016, Tanzania, Uluguru Mts., Bunduki village, 07°01′17″S, 37°39′10″E, 1592 m asl, mid-altitude afromountain deciduous forest, litter sifting 21, 26.XI.2010, leg. V. Grebennikov.

Description

Measurements of the holotype (specimen from sample TAN-007).

Prodorsum. Length 252, height 101, width 202, sensillum 78, setae: interlamellar 164, lamellar 109, rostral 126, exobothridial 15; notogaster: length 459, height 308, width 333, setae: c₁ 78, c₁/c₁ − d₁ = 0.77, cp 91, h₁ and p₁ 71; genitoaggenital plate 157 × 71, length of seta g₇ 43, length of seta g₆ 23, anooadanal plate 207 × 51.

Species of medium size. Colour brown. Integument punctuate.

Prodorsum with one pair of medium length, lateral carinae; sensilla with short, narrow pedicel and fusiform head, covered with tiny spines at top; setae rigid, long, interlamellar and rostral covered sparsely with thin spines, lamellar setae rather smooth, exobothridial setae minute.

Notogaster with short (c₁ < c₁ − d₁), thick but flexible setae, pointed distally and covered sparsely with thin spines, setae of row c remote from anterior margin, setae c₁ more, setae c₃ less, setae cp considerably longer than setae c_1–3.

Ventral region. Setae h of mentum considerably longer than distance between them. Genital plates dentate in anterior part; seven pairs of genital setae present, setae g₇ the longest, setae g_4–6 shorter, setae g_1–3 (in progenital position) shortest, two pairs of aggenital setae ag₂ slightly longer than ag₁; anoadanal plates each with three pairs of anal and three pairs of adanal setae, anal setae shorter than adanal setae, anal setae an₁ and an₂ smooth, flagellate, other setae more rigid and covered sparsely with thin spines, setae ad₃ situated near setae an₃, lyrifissures iad located laterally and slightly posteriorly of setae an₃.

Chaetome of legs. 1–3–5(2)–5(1), II: 1–4–3(1)–5(1), III: 2–2–2(1)–2(1), IV: 2–1–1(1)–2(1). Tarsi heterotridactylous.

Etymology

Prefix para is Latin meaning “near” and refers to the similarity of the new species with E. (P.) kunsti Starý, 1988.

Remarks

The new species is distinguishable from congeners by the genital setae g₇ considerably longer than the other genital setae, lamellar setae longer than rostral setae, setae cp longer than the other notogastral setae, and setae ad₃ situated near setae an₃. The new species is distinguishable from E. (P.) kunsti by the presence of three pairs of genital setae in progenital position (vs two pairs of setae), genital setae g₇ longer than other (vs all genital setae equal in length), and lyrifissures iad positioned posteriorly of setae an₃ (vs iad on the level of an₃).

List of known Pocsia species

Euphthiracarus (Pocsia) africanus (Mahunka, 1983), Tanzania; bicarinatus (Starý, 1991), Kenia; disparilis Niedbała, 1998, Kenia; dubius Niedbała & Schatz, 1996, Guatemala; heterotrichus (Mahunka, 1988), Tanzania, Democratic Republic of the Congo; inopinatus (Niedbała, 1993), Democratic Republic of the Congo; insolitus Niedbała, 2004, Cuba; kunsti (Starý, 1988), Tanzania; microsetus Starý, 1993, Cuba; paraafricanus Niedbała & Stary, 2014, Tanzania; paradisparilis Niedbała, 2004, Brazil; parakunsin. sp., Tanzania; sarawaki Niedbała, 2000, Malaysia; secundus (Mahunka, 1983), Tanzania; sudamericanus Niedbała, 2004, Brazil; trentus (Mahunka, 1983), Tanzania; and uluguruensis Niedbała & Stary, 2014, Tanzania.

Remarks

So far, 17 species of Euphthiracarus (Pocsia) are known. The majority of them (11 species) have been found in the Afrotropical Region (Mahunka 1983, 1988; Starý 1988, 1991; Niedbała 1993, 1998; Niedbała and Starý 2014), mainly in East Africa, and particularly in Tanzania (eight species). Five species are known from the Neotropical Region, two from Cuba, two from Brazil, and one from Guatemala (Starý 1993; Niedbała and Schatz 1996; Niedbała 2004). Only one species occurs in the Oriental Region in Malaysia (Niedbała 2000).

The African species show considerable morphological differences from those found in the other zoogeographical regions, but the morphological differences between the African species are very small and the species are extremely similar.

Key for identification of Euphthiracarus (Pocsia) species

	1 Two pairs of prodorsal lamellar carinae present …………………………………………2
	– Only one pair of lateral carinae present …………………………………6
	2 Sensilla with distal fusiform head ……………………………………………………3
	– Sensilla without head, rodlike, tapering distally …………………………………………4
	3 All genital setae minute and similar in length, aggenital setae ag2 considerably longer than ag1…………………………………………bicarinatus
	– Genital setae g7 and g8 longer than other, aggenital setae almost equal in length …………………………………………………… sudamericanus
	4 Seven pairs of genital setae present, aggenital setae ag2 longer than ag1, lyrifissures iad positioned posteriorly of ad3 setae …………………………………………………… dubius
	– Eight pairs of genital setae present, aggenital setae similar in length, lyrifissures iad positioned anteriorly of ad3 setae ………………………………………………………… 5
	5 Sensilla relatively shorter than high of prodorsum, lyrifissures iad positioned slightly anteriorly of an3 setae ………………………………………………………… paradisparilis
	– Sensilla relatively longer than high of prodorsum, lyrifissures iad positioned slightly posteriorly of an3 setae ……………………………………………………………… sarawaki
	6 All genital setae minute, similar in length ……………………………………………… 7
	– Some of genital setae distinctly longer than other …………………………………… 10
	7 Seven pairs of genital setae present ……………………………………………………… 8
	– Eight pairs of genital setae present ……………………………………………………… 9
	8 Notogastral setae cp longest, setae c3 shortest, two pairs of genital setae in progenital position, aggenital setae almost equal in length ……………………………………… kunsti
	– All notogastral setae relatively similar in length, no one genital setae in progenital position, aggenital setae ag2 considerably longer than ag1 ………………………………… inopinatus
	9 Sensilla swollen in proximal part, distance between an2 and ad3 greater than between setae an1 and an2 …………………………………………………………………………… insolitus
	– Sensilla swollen in distal part, distance between an2 and ad3 smaller than between setae an1 and an2………………………………………………………………………… microsetus
	10 Sensilla rod-like, tapering distally …………………………………………… disparilis
	– Sensilla fusiform ……………………………………………………………………… 11
	11 Tarsi of leg monodactylous …………………………………………………………… 12
	– Tarsi of legs heterotridactylous ………………………………………………………… 14
	12 Seven pairs of genital setae present …………………………………………… secundus
	– Six pairs of genital setae present ……………………………………………………… 13
	13 One pair of genital setae in progenital position, genital setae g6 longest ……………………………………………………. paraafricanus
	– No one genital setae in progenital position, genital setae g5 and g6 longest ……………………………………………………. . heterotrichus
	14 Five pairs of genital setae present, only one pair of genital setae in progenital position ………………………………………………………………………………………… trentus
	– Six or seven pairs of genital setae present, three pairs of genital setae in progenital position ……………………………………………………………………………………………… 15
	15 Rostral and lamellar setae situated in equal horizontal level, seven pairs of genital setae present, only one pair of setae g7 longest ……… ………………………… parakunstin. sp.
	– Rostral setae positioned slightly posteriorly of lamellar setae, six pairs of genital setae present, two pairs genital setae g5 and g6 longest ……………………………………… 16
	16 Notogastral setae c3 and cp longest, aggenital setae similar in length, lyrifissures iad situated posteriorly of setae an3 ………………………………………………… africanus
	– Notogastral setae c3 shortest, setae cp longest, aggenital setae ag2 twice as long as ag1, lyrifissures iad situated at level of setae an3 ………………………………… uluguruensis

Acknowledgements

The author thanks Dr J. Stary, Institute of Soil Biology, České Budějovice for lending samples from Tanzania in which the new species was found. Many thanks are due to the two anonymous reviewers for their critical reading of the manuscript and important suggestions.