Monographis tamdaoensis, Huynh, 2022

Huynh, Cuong, 2022, Four new species of Monographis Attems, 1907 (Diplopoda, Polyxenida, Polyxenidae) from Vietnam, Zootaxa 5214 (3), pp. 393-420 : 407-409

Monographis tamdaoensis new species

Figures 13–17

Material examined: Holotype, adult male (IEBR-Myr 989) and paratypes: Adult, two males (IEBR-Myr 990) two females (IEBR-Myr 991) and, two subadults with 12 pairs of legs (IEBR-Myr 992) were collected from Tam Dao National Park , 21.458611N, 105.649444E, elevation 1017 m, Vinh Phuc Province, northern Vietnam. All types were deposited in the Institute of Ecology and Biological Resources , Vietnam. Specimens were collected by author CH in the field trip organised by Dr Duc Anh Nguyen, on 17 th July 2017.

Diagnosis: Body length 2.4–3.2 mm. Antennal article VI with 16–18 bacilliform sensilla forming crescent shape, setiform sensillum located in anterior position, conical sensillum present near centre of crescent. Labrum asetose, long slender anterior setae in anterior margin. Telotarsus with posterior lateral process shorter than half-length of claw, anterior lateral and lamella processes present, anterior setiform process shorter than half-length of claw.

Description:

Holotype male body 2.4 mm; paratypes: males 2.2–2.4 mm, females 3.0– 3.2 mm; caudal bundle 0.5 mm, nest trichomes 0.2 mm.

Head: Arrangement of post vertex trichomes as for Monographis cattienensis with the holotype having 13 sockets (L) and 14 ( R) in anterior rows, posterior rows with 3 sockets on both sides ( Figures 13A & 13B ). Paratype showed anterior rows with 12–14 sockets, posterior rows with 2–3 sockets ( Figure 16A ). Clypeo-labrum: Holotype, labrum posterior margin with 8 setae (Se), these setae longer in length than labrum width (paratype with 8–10 setae). Labrum surface asetose (l), labrum posterior margin has a row of minute backward-pointing setae (sb). Lateral lamella (Ll) and single broad lamella each side median cleft (mc), 12–14 slender setae (sa) present on anterior margin of labrum ( Figures 13C & 16D ) .

Antennae: Antennal article VI with 16–18 bacilliform sensilla. Holotype with 16 bacilliform sensilla forming a crescent shape with 3 thick ( T), 9 thin bacilliform sensilla (t) and 4 medium-length thin bacilliform sensilla (tm), setiform sensillum (S) located in anterior position, conical sensillum (C) present near centre of crescent ( Figures 14C , 17B &17C ).

Telotarsus: Claw slender, posterior lateral process (p) shorter than half-length of claw, anterior lateral (a) and lamella processes (la) present, anterior setiform process (s) less than half-length of claw (c). ( Figures 15B & 17D ).

Telson: Arrangement of dorsal ornamental trichome sockets similar to M. cattienensis with 17 sockets of trichomes a left side and 18 sockets on right side of the telson in the holotype (paratype with 16–18 sockets). ( Figure 15C ).

Remarks: Monographis tamdaoensis sp. n. is distinguished from congeners in its labrum structures and anterior setiform process equal to half-length of claw.

Etymology: Monographis tamdaoensis is named after Tam Dao National Park in Vinh Phuc Province, Vietnam.

Figures

FIGURE 13. Holotype male Monographis tamdaoensis sp. n.. A. Head capsule with eye patterns, posterior vertex (pv) trichome sockets and the trichobothria (a, b and c). B. Enlarged images of Posterior vertex trichome sockets on left and right side; C. Clypeo-labrum with asetose labrum surface (l), lateral labrum (Ll) on each side, anterior setae (sa), posterior setae (Se), backward pointing setae (sb).

FIGURE 14. Holotype male Monographis tamdaoensis sp. n.. A. Section of antennal articles VI–VII and sensory cones (sc), and their sensilla. B. Sensilla on the antennal article VII, with two thick bacilliform sensilla (Ta & Tp), setiform (S) and a conical sensillum (C). C. Sensilla on the article VI, showing thick (T), thin (t) and medium thin bacilliform sensilla (tm).

FIGURE 15. Holotype male Monographis tamdaoensis sp. n.. A. The second leg showing its segments and chaetotaxy, penis (p). B. Telotarsus showing the claw (c) and processes: anterior (a), posterior (p), lamella (la) and anterior setiform process (s) shorter than half length of the claw (dot line). C. The ornamental trichome sockets with trichomes a, b, three c and an indented d.

FIGURE 16. SEM images of Monographis tamdaoensis sp. n.. A. Posterior vertex (pv) showing the arrangement of trichome sockets. B. Left eye pattern with eight ommatidia and the trichobothria: a, b and c. C. Gnathochilarium showing the medial palp (Mp) andlateral palp (Lp) with 11 sensilla. D. Clypeo-labrum showing asetose surface (l), backward pointing setae (sb), anterior setae (sa), posterior setae (Se), lateral labrum (Ll) and the medial cleft (mc).

FIGURE 17. SEM images of Monographis tamdaoensis sp. n.. A. Antennal article VI–VIII. B. Arrangement of a setiform (S), conical sensillum (C), thick (T), thin (t) bacilliform sensilla, and the medium length bacilliform sensilla (tm) on article VI. C. Other end of arrangement of sensilla on article VI. D. Telotarsus and its processes: claw (c), anterior setiform process (s), lamella (la), anterior (a) and posterior (p) processes.