Phymatodiscus insolitus, Jenő Kontschán & Géza Ripka, 2016

Jenő Kontschán & Géza Ripka, 2016, Three new Uropodina mites (Acari: Mesostigmata) from Singapore, Revue suisse de Zoologie 123 (2), pp. 291-301 : 292-296

Phymatodiscus insolitus sp. nov.

Figs 12-22

Holotype: MHNG, sample Bru-88/5 ; female; “ Singapore, Island Country Club, situé entre Lower Peirce Resevoir et Windsor Park Estate , restes de forêt primaire entourés de forêt secondaire, prélèvement de sol au pied d’un grand arbre vivant, env. 60 m; 12.XI.1988 ”; leg. B. Hauser (Berlese à Bandar Seri Begawan, Brunei).

Paratypes: MHNG; two females; locality and date same as for holotype.

Diagnosis: Eye-like transversal furrows small and partly covered by dorsal shield. Four pairs of marginally serrate setae situated in caudo-central part of dorsal shield. Genital shield of females scutiform, ventral setae posterior to genital shield short and needle-like. Five (P. aoki Hiramatsu, 1985; P. haradai Hiramatsu, 1985 ; P. kuni Kontschán & Starỳ, 2011; P. malayicus Kontschán & Starỳ, 2012 and P. oculatus Hirschmann in Hirschmann & Hiramatsu, 1977) of the described Phymatodiscus species have one pair of deep, eye-like, transversal furrows bordered with long setae on level of coxae IV, but in the new species these furrows are small and not bordered with long setae.

Description of female: Length of idiosoma 1100-1120, width 933-1000 (n=3). Shape of idiosoma circular, posterior margin rounded, color reddish brown.

Dorsal side of idiosoma ( Fig. 12 ): Marginal and dorsal shields fused anteriorly. Margins of dorsal shield with small oval pits ( Fig. 18 ), majority of dorsal setae short, smooth and needle-like (about 27-34 long), some setae on margins of dorsal shield marginally pilose ( Fig. 18 ). Three pairs of short, pilose and three pairs of longer (about 50-55), smooth setae situated close to caudal margin of dorsal shield. One pair of small eye-like transversal furrows situated at level of coxae IV, between and posterior to furrows with three pairs of apodemes.

Two pairs of marginally serrate setae (about 33-34 long) visible between second and third apodemes, and other two pairs of similar setae (about 42-44 long) posterior to third apodeme. Marginal shield with two rows of smooth and needle-like setae (about 20-27 long), first row situated on small platelet, second row without platelets. Pores placed close to each marginal seta ( Fig. 18 ).

Ventral side of idiosoma ( Fig. 13 ): Sternal and ventral shields without ornamentation, only two large apodemes visible at level of metapodal line. Four pairs of sternal setae smooth and needle-like (about 13-17 long), setae St1 situated close to anterior margins of sternal shield, St2 at level of anterior margins of coxae III, St3 at level of anterior margin of coxae IV, St4 at level of posterior margins of coxae IV. St5 absent. Six pairs of ventral setae smooth and needle-like (about 14-17 long), other two pairs of ventral setae similar in shape and length to others but raised on small platelets. Two pairs of long (about 88- 90 long) and robust setae situated on caudal margin, and numerous long (about 64-67 long) and marginally pilose setae present on margins of ventral idiosoma. Numerous pores situated close to pilose marginal setae, and one pair of lyrifissures posterior to end of pedofossae IV. Adanal and postanal setae very short (about 14-18 long) and placed around genital opening. Stigmata situated between coxae II and III. Prestigmatid part of peritremes hook-shaped, poststigmatid part short. Genital shield scutiform, anteriorly pointed, with smooth surface. Base of tritosternum ( Fig. 17 ) narrow, tritosternal laciniae pilose and divided into three branches. Pedofossae deep, their surface smooth, separated furrows for tarsi IV present.

Gnathosoma ( Fig. 14 ): Corniculi horn-like, internal malae longer than corniculi and marginally pilose. Hypostomal setae as follows: h1 long (about 80-85), smooth and needle-like, situated posterior to basal line of corniculi; h2 short (about 19-20), smooth and robust; h3 long (about 29-31) and marginally serrate; h4 long (about 26-28) and apically serrate. Anterior part of epistome slightly pilose, proximal part serrate ( Fig. 15 ). Palp with smooth setae except for one short and one extremely long serrate seta on ventral part of palpal trochanter ( Fig. 16 ). Chelicerae not clearly visible.

Legs ( Figs 19-22 ): Claws absence from tip of leg I, all legs bearing smooth and needle-like setae.

Male, larva and nymphs unknown.

Etymology: The name of the new species refers to the unusual (= “ insolitus ” in Latin) shape and position of its eye-like transversal furrows.

Figures

Figs 12 - 17. Phymatodiscus insolitus sp. nov., female holotype. (12) Body in dorsal view. (13) Body in ventral view. (14) Ventral view of gnathosoma. (15) Epistome. (16) Ventral view of palp. (17) Tritosternum.

Figs 18 - 22. Phymatodiscus insolitus sp. nov., female holotype. (18) Setae and ornamentation on dorsal and marginal shields. (19) Ventral view of leg I. (20) Ventral view of leg II. (21) Ventral view of leg III. (22) Ventral view of leg IV.