Hirschmann (1975) divided the genus Trigonuropoda into several species groups, which were mentioned later as “Stadiengattung” (maybe subgenus) in his new system (Hirschmann 1979). Kontschán (2008) used the cubabaloghia species group as Baloghiatrigon subgenus after Hirschmann's (1979) system, therefore we follow this logic in this paper as well, and we placed the new species into the Foveolatatrigon Hirschmann, 1979 subgenus, which was discussed as “difoveolata-group” in other Hirschmann's systems (Wiśniewski & Hirschmann 1993). Species of the subgenus Foveolatatrigon are easy to separate from the other trigonuropodid species on the basis of the following combination of characters: (1) the inner margin of the marginal shield is undulate, (2) anterior pit absent on the dorsal idiosoma, and (3) caudal area is not elevated from the neighbouring regions of the dorsal shield.

The species of the subgenus Foveolatatrigon are recorded from Philippines, Taiwan, Japan, Indonesia, Malaysia, New Guinea, Australia and Peru (Wiśniewski 1993). This tropical and subtropical distribution suggested that Foveolatatrigon can be found in the Afrotropics as well; hence the finding of a new species has not been unexpected.

Etymology: We dedicate this species to two renowned Hungarian acarologists, Prof. Sándor Mahunka (1937–2012) and his wife Luise (“Csibi”) Mahunka-Papp (1937–2011), for their enormous contribution to the knowledge of the world, and especially Malagasy, oribatids.

Description:

Female.

Idiosoma: Length 620–630 µm, width 450–460 µm (n=2). Shape oval, posterior margin rounded.

Dorsal aspect (Fig. 1). Dorsal and marginal shield completely separated. Dorsal setae short and spine-like (ca 25–27 µm) anteriorly, and wide and phylliform (ca 36–44 µm) posteriorly. Dorsal shield covered by oval pits. Marginal shield with undulate inner margin, marginal setae smooth and needle-like (ca 17–23 µm), surface of marginal shield smooth (Fig. 2).

Ventral aspect (Fig. 3). Sternal shield without sculptural pattern, but some oval pits situated near coxal margins. All sternal setae short (ca 8–10 µm), smooth and needlelike. St1 situated at level of anterior margin of coxae II, St2 at level of central area of coxae II, St3 at level of anterior margin of coxae III, St4 at level of central area of coxae III, St5 placed near basal edges of genital shield (Fig. 6). Two pairs of lyriform fissures situated on sternal shield, first pair near to St1, second pair near to St5. Ventral shield neotrichous; smooth and needle-like setae (ca 15–23 µm) situated between pedofossae of legs IV. Ventral shield also covered by oval pits. Posterior part of this region with numerous bulbiform setae (ca 20–22 µm) can be seen on small protuberances. At level of anal opening, surface covered by small, funnel-like pits (Fig. 5). First pair of adanal setae (ad1), narrow and needle-like (ca 11–12 µm), second pair (ad2) wider and apically pilose (ca 18–20 µm). One pair of lyriform fissures situated between ad1 and ad2 (Fig. 5). Pedofossae deep, their surface smooth, separate furrows for tarsi IV absent. Peritremes short, prestigmatid part Z-like, post-stigmatid part straight (Fig. 4). Stigmata situated between coxae II and III. Genital shield linguliform situated between coxae II and IV, surface with oval pits; without anterior process. Tritosternum with narrow basis, tritosternal laciniae divided into three, marginally serrate branches (Fig. 7). Gnathosoma (Fig. 8): Corniculi horn-like, internal malae short, triangular and marginally smooth. Hypostomal setae h1 smooth, apically wide and Y-shaped (ca 43 µm), h2 smooth, needle-like and very short (ca 12 µm), h3 long (ca 44 µm) and smooth, h4 apically serrate (ca 27 µm). Epistome with serrated basal margin, apically pilose (Fig. 9). Digitus fixus of chelicerae without teeth and longer than digitus mobilis, digitus mobilis with one central tooth, internal sclerotized node present (Fig. 10). Palp with smooth and needle-like setae (Fig. 11).

Legs (Figs 13–16): All legs with ambulacral claws and bearing smooth setae on all segments except tarsi. Tarsi II–IV with long marginally serrate and short robust apically serrate setae Leg I–II with large lateral flaps on femurs.

Male.

Idiosoma: Length 590 µm, width 440 µm (n=1). Shape oval, posterior margin rounded. Dorsal pattern and chaetotaxy similar to that of female.

Ventral aspect: Sternal shield covered by oval pits. Sternal setae smooth, short (ca 8–10 µm) and needle-like. St1 situated at level of anterior margin of coxae II, St2 at level of posterior margin of coxae II, St3 at level of anterior margin of coxae III, St4 at level of anterior margin of coxae IV, St5 at level of central area of coxae IV, near margin of genital opening. Two pairs of lyriform fissures situated, first pair near to St1, second pair between St4 and St5 (Fig. 12). Ventral chaetotaxy similar to that of female. Genital shield circular, situated between coxae IV.

Larva and nymphs. Unknown.

Holotype: ♀ MADAGASCAR: Ranomafana National Park, 21°14′51″S 47°24′13″E, 1079 m, litter sifting, 16–18.xi.2010, P. Baňař (HNHM).

Paratypes: 1 ♀ 1♂ same data as for holotype (♀ ISB, ♂ HNHM).

Comparison: The new species has several unique characters in the Foveolatatrigon subgenus. The new species has linguliform genital shield, which is scutiform in other Foveolatatrigon species. The post-stigmatid part of peritreme is short in the T. (F.) mahunkaorum, but longer in the other species of the subgenus. The bulbiform setae of the caudal area of the ventral shield, which can be found in T. (F.) mahunkaorum, are unknown in other Foveolatatrigon species.