Mnesilochus bodiense, Hennemann, 2021

Hennemann, Frank H., 2021, Stick insects of Sulawesi, Peleng and the Sula Islands, Indonesia- a review including checklists of species and descriptions of new taxa (Insecta: Phasmatodea), Zootaxa 5073 (1), pp. 1-189 : 42-44

Mnesilochus bodiense n. sp.

( Fig. 17 )

Phasgania furcata, Günther, 1935: 11 , pl. 1: 6.

HT, ♂: Nord-Celebes, Bodi, 30.9.1930, G. Heinrich leg. [ MNHU] .

Etymology: Named after Bodi, the type-locality and only known record of this small new species.

Differential diagnosis: While fairly typical in general shape for the genus, ♂♂ (the only sex known) of this small species are easily separated from the ♂♂ of all other known species of the genus by the very broad and in lateral aspect obtusely rounded hemi-terga of the anal segment ( Fig. 17C ), which are usually more acuminate and slender in the other species. The very small size (body length of the holotype 62.0 mm) resembles the two Bornean M. bushelli (Bragg, 2005) and M. rusticus (Brunner v. Wattenwyl, 1907) but those ♂♂ are much more stocky in shape and have rather triangular hemi-terga of the anal segment with an acuminate apex.

Description: ♂ ( Fig. 17 ). The unique holotype lacks the right front leg, left protarsus, right mesotibia and metatarsus and the right antenna except for the two basal segments. Thus, no description of the taxonomically important protarsi can be provided.

Small (body length 62.0 mm) and of average, rather typical shape for the genus. General colour ochraceous brown, eyes buff, antennae dark reddish brown (except for the two basal segments, which are coloured like the body). Entire body surface densely granulose, the granules however less in number and notably less pronounced on abdomen and gradually becoming fewer in number and smaller in size towards apex of abdomen; granules of the thorax glossy. Abdominal terga with a very fine medio-longitudinal line.

Head: Longer than wide, broadest at the eyes with the genae notably narrowing towards the posterior ( Fig. 17A ). Vertex flat and between the eyes with a raised area that is densely set with glossy granules and bears two very obtuse tubercles. Coronal line of vertex indistinct. Eyes large, circular in outline, projecting hemispherically and their diameter contained 1.7x in length of genae. Antennae slightly projecting over posterior margin of median segment. Scapus compressed dorsoventrally, almost rectangular and weakly narrowed basally, 2x longer than wide. Pedicellus cylindrical and about 1/3 the length of scapus.

Thorax: Pronotum roundly rectangular and very weakly narrowed medially, 1.5x longer than wide and narrower than broadest portion of head. Transverse median sulcus moderately distinct, straight and not reaching to lateral margins of segment. Mesothorax very elongate, slender, weakly widened at anterior margin and distinctly broadened and slightly swollen in posterior portion; 7.1x longer than pronotum. Metanotum 0.6x the length of mesonotum with the posterior 1/3 slightly thickened ( Fig. 17A ). Meso- and metasternum and pleurae without specializations.

Abdomen: Median segment as wide as posterior portion of metanotum, a little less than ¼ the length of metanotum, slightly narrowed medially and a about 1.6x longer than wide. Segment II about 1.7x longer than median segment. II–VI uniform in width and almost uniform in length, on average 3x longer than wide. VII only about ¾ the length of preceding and slightly widened posteriorly. Sterna II–VII simple. Terga VIII and IX acutely keeled medio-longitudinally and with lateral margins weakly concave; VIII moderately widened towards the posterior, widest segment and slightly shorter than VII; IX transverse and less than half the length of VIII. Anal segment tectiform and split longitudinally to form two movable hemi-terga, which are connected by a membrane in the basal portion; in lateral aspect these are rather broad with the apical portion short, obtusely rounded and somewhat downward directed ( Fig. 17C ), the interior surface is irregularly set with small denticles. Cerci short and conical with a fairly acute apex. Poculum small, cup-shaped and with a rounded posterior margin, that slightly projects beyond tergum IX ( Fig. 17C ).

Legs: Long, distinctly carinate with the mesofemora moderately thickened and smooth dorsally; profemora almost as long as mesothorax, metafemora reaching to posterior margin of abdominal segment IV and metatibiae reaching to abdominal segment IX. Posteroventral carina of profemora with a one small sub-apical tooth. Two outer ventral carinae of meso- and metafemora each with three closely placed sub-apical teeth that gradually decrease in size towards the apex of femur; those of the mesofemora with a common base ( Fig. 17B ). Meso- and metabasitarsi about as long as following three tarsomeres combined; slender.

Comments: Females and eggs unknown. Günther (1935: 11) erroneously assigned this specimen to Dixippus furcatus Brunner v. Wattenwyl, 1907, which is a synonym of Periphetes forcipatus ( Bates, 1865) , and provided a description. The possible unknown opposite sex of this small new species may be represented by the ♀ from Luwu, South Sulawesi in NHMB and erroneously referred to as H. haematomus ( Westwood, 1859) by Günther (1938: 78). This particular specimen is definitely not the opposite sex of the ♂ assigned to H. haematomus by that author in NHMB and from the same locality; this is a paratype of Hermagoras celebensis ( Hennemann, 1998) . If compared to the holotype of M. bodiense n. sp. the ♀ in NHMB (here described as M. luwuense n. sp.) appears to be too large, having a body length of 102.0 mm, thus is clearly outside the average size diversity between corresponding sexes within Mnesilochus . However, since both sexes of species in this genus can show considerably size ranges fresh material from the same locality will be necessary for any confirmed decision.

Distribution: Central Sulawesi, Prov. Sulawesi Tengah, Buol Regency, Bodi [MNHU].

Figures

FIGURE 17. Mnesilochus bodiense n. sp. ♂, holotype [MNHU]: A. Habitus dorsal view; B. Habitus, dorso-lateral view; C. Terminal abdominal segments seen laterally.