Pseudosundanina falcata ( Attems, 1937 ) Attems, 1937

Nguyen, Anh D., 2010, The millipede tribe Sundaninini in Vietnam (Diplopoda: Polydesmida: Paradoxosomatidae), Zootaxa 2479, pp. 59-68 : 60-62

Pseudosundanina falcata ( Attems, 1937) , new combination

Figs. 1–11.

Material studied: 3 ♂♂, 1 Ψ: ( IEBR) Vietnam, Lamdong Prov., Bi Doup – Nui Ba National Park, 12 0 09’N, 108 0 39’E, primary evergreen broad–leaved forest, 1800 m, 15/3–23/4 /2008, leg. Nguyen Duc Anh; 1 ♂, 2 ΨΨ: ( IEBR) same locality, 12 0 06’N, 108 0 38’E, Peak Bi Doup, 2000 m, leg. A. Abramov.

Description: A medium–sized paradoxosomatid 22.5–23.4 mm (♂) or 23.8–26.3 mm (Ψ) long, width of midbody pro– and metazona 1.8–2.1 and 2.1–2.4 mm (♂) or 1.9–2.3 and 2.4–2.8 mm (Ψ), respectively.

Coloration generally yellowish brown. Head yellowish brown with a darker frons. Metazona castaneous brown with a yellowish area in the middle, surrounding both an axial line and a transverse metatergal sulcus.

Prozona and pleura yellowish brown, sterna yellowish. Antennae yellowish brown, but distal part of antennomere 5 and entire antennomeres 6 and 7 blackish brown. Legs brownish yellow with darker tibiae and tarsi.

Head only sparsely setose near labrum. Epicranial suture very distinct. Antennae rather long and slender, slightly clavate, about reaching the end of segment 2.

Body: Width of head <collum = segment 4 <3 <2, paralled–sided on segments 5–17, thereafter tapering towards telson. Surface of metaterga smooth, with traces of 3(4)+3(4) and 3(4)+3(4) setae in two rows, one in front of, the other behind transverse sulcus, near caudal margin of metaterga. Two dark brown parts on metaterga interrupted by a yellowish part in the middle providing an evident pattern (Fig. 1). Axial line vague on collum and segments 2–5, thin but distinct from segment 6 onward. Transverse metatergal sulcus distinct, moderately deep from segment 4 onward, beaded at bottom, nearly reaching the base of paraterga, slightly arcuate anteriad near middle. Prozona and pleura smooth. Stricture dividing pro– and metazona moderately deep, obviously longitudinally striolate dorsally. Pleurosternal carinae well–developed until segment 10, thereafter vague and reduced. Paraterga small, poorly–developed, set low (at about half of metazonital height). Calluses very small, thin in dorsal view, bordered only dorsally but either not bordered ventrally on poreless segments or bordered ventrally only in rear halves on pore–bearing segments. Both front and caudal corners of paraterga 2–4 rounded, thereafter only front corner remaining rounded while caudal one growing increasingly acute, especially so on pore–bearing segments. Ozopores dorsolateral, visible also in dorsal view, located inside an ovoid groove near caudal corner of paraterga.

FIGURES 1–6. Pseudosundanina falcata ( Attems, 1937) , comb. nov., ♂♂ from 12 0 09’N, 108 0 39’E: segment 10, dorsal view (1); sternal lobe between male coxae 4, posteroventral view (2); telson, ventral view (3); left gonopod, mesal view (4), lateral view (5), dorsal view (6). Scale bar = 1 mm

Epiproct stout and broad, slightly concave laterally, curved down, tip emarginated, preapical papillae undeveloped. Hypoproct subtraperziform, with two setiferous knobs at caudolateral corners (Fig. 3).

Sterna sparsely setose, without modifications, cross–impressions moderate; a subtriangular, apically broadly rounded, setose lamina between male coxae 4 (Fig. 2). Legs relatively long and slender, in both male and female about 1.2 times as long as midbody height. Ventral brushes well–developed, present on tibiae until segment 13, on tarsi until segment 12, thereafter thinning out and reduced. Femora unmodified.

Gonopods (Figs. 4–9) relatively simple. Coxa long and subcylindrical, distoventral part modestly setose. Prefemoral part as usual densely setose, short. Femorite slender and long, about as long as coxite, demarcated from postfemoral portion (= solenophore) by a very evident subtransverse sulcus laterally, with a long, curved, well–developed, slender process (sp) distally near base of a flagelliform solenomere, but without additional sulci. Solenophore very long and slender, much longer than femorite or coxite, devoid of parabasal outgrowths, strongly falcate, with both a lamina medialis (lm) and, especially, a lamina lateralis (ll) well– developed, sheathing virtually entire solenomere; tip divided into three lobes.

Remarks: The above new samples derive from the Bi Doup – Nui Ba National Park which is very close to Dalat, the type locality of Sundanina falcata Attems, 1937 . In comparison with the gonopods of syntype material, currently kept in the Vienna Museum in Austria (Fig. 10 – 11), and based on the literature, most of the characteristics of the new samples fit the available descriptions well ( Attems, 1937, 1938), slightly differing in size (2.1 and 2.4 mm versus 1.32 and 1.65 mm in pro– and metazona width, respectively).

FIGURES 7–11. Pseudosundanina falcata ( Attems, 1937) , comb. nov., ♂♂ from 12 0 09’N, 108 0 39’E: left gonopod, postfemoral region, dorsal view (7), mesal view (8), tip of gonopod, dorsal view (9); from syntype (Vienna Museum, Austria) (10), and from literature (11, redrawn after Attems, 1937)