Ramulus melanurus, 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 : 74-76

Ramulus melanurus n. sp.

( Fig. 30 )

Baculum globosicaput, Günther, 1935a: 2 .

HT, ♂: Celebes, Latimodjong-Geb., Oeroe , 800 m, G. Heinrich 8.30 [ MNHU]

Etymology: The name ( melanurus lat. = blacktail) refers to the black three terminal abdominal segments of ♂♂ of this new species ( Fig. 30B ).

Differential diagnosis: Males, the only sex known, differ from all other species so far known from Sulawesi by the typical colouration, being uniformly orange with only the complete antennae and three terminal abdominal segments contrasting black. The most similar species is R. torajanus n. sp., but morphologically ♂♂ of this new species can be distinguished by the almost spherical head, posteromedian humps on abdominal terga V and VI and the comparatively more elongate and slender hemi-tergites of the anal segment.

Description: The following description is based on the unique holotype, which unfortunately lacks both pro-and metatibiae and the left mid leg.

♂ ( Fig. 30A ). Of average size (body length 88.0 mm) for the genus, moderately thin and stick-like with an almost spherical head and characteristic colouration. General colour uniformly dull orange with faint dark brown hues on abdominal terga II and III. Complete antennae including scapus and pedicellus and terminal three abdominal segments black; cerci orange. Head with two very faint, washed brown markings between the eyes and the bases of the antennae black. Mesotibiae with a slight greenish wash.

Head: Large, almost spherical and smooth; broadest just behind the eyes ( Fig. 30C ). Between the bases of the antennae with a shallow indention and between the eyes with two very slightly swollen areas. Eyes very large, projecting more than hemispherically and their diameter contained about 1.6x in length of genae. Antennae almost reaching apex of profemora and laid back reaching about half way along metanotum. Scapus compressed dorsoventrally, somewhat narrowed towards the base and about 2x longer than wide; the interior margin very gently convex. Pedicellus cylindrical and about half the length of scapus. Antennomere III longer than scapus and pedicellus combined.

Thorax: Pronotum shorter and much narrower than head ( Fig. 30C ), roundly rectangular in outline with the anterior portion slightly expanded laterally; remainder of the lateral margins parallel-sided. Transverse median sulcus fairly distinct, impressed, straight and almost reaching lateral margins of segment. Mesothorax very elongate and almost 8.5x longer than prothorax but just 1.2x longer than metanotum; very gently widened posteriorly. Metathorax somewhat constricted medially.

Abdomen: Median segment roughly rectangular, just slightly longer than wide and only 0.2x the length of metanotum. Segment II about 3x longer than median segment. II–V uniform in length, VI and VII slightly decreasing in length with VII only about 2/3 the length of II–V; all uniform in width and very slightly widened posteriorly. II–V almost 5x and VII only 3.5x longer than wide. Terga V and VII with posterior margin swollen and raised to form an obtus, conical median hump. Terga VIII–X broader than all preceding, VIII only half the length of VII but distinctly widening towards the posterior with the lateral margins somewhat deflexed and roundly convex. Tergum IX slightly shorter than VIII and almost quadrate in dorsal aspect. Anal segment almost as long as VIII and IX combined, split longitudinally and strongly tectiform; the hemi-terga in lateral aspect with the apical half gradually narrowing, very gently up-curving and obtusely rounded at the apex ( Fig. 30B ), interiorly armed with several small, blackish teeth. Cerci slender, gently in-curving and narrowed in the apical portion. Poculum very small, scoop-shaped, obtusely keeled longitudinally and with the posterior margin somewhat labiate; reaching to posterior margin of tergum IX ( Fig. 30B ).

Legs: All long and very slender; unarmed except for a single, minute and fairly blunt sub-apical tooth on the medioventral carina. Profemora almost 1.4x longer than head, pro- and mesothorax combined, mesofemora slightly longer than head, pro- and mesothorax combined and metafemora reaching to posterior margin of abdominal segment VI. Mesobasitrarsus 1.25x longer than combined length of remaining tarsomeres.

Comments: The unique ♂ holotype from Uru in the collection of MNHU was misidentified as R. golobosicaput by Günther (1935a: 2). Comparison with the holotype of that species show the specimen to differ by the almost spherical and plain orange head, which only has two very faint darker spots between the eyes, black scapus and pedicellus, the black three terminal abdominal segments and slender hemi-tergites of the anal segment. Hence, it is here described as a new species. Female and egg unknown.

Distribution: So far only known from Uru, at Mount Rantemario in the Latimojong Mountains of South Sulawesi (Province Sulawesi Selatan).

Figures

FIGURE 30. Ramulus melanurus n. sp. ♂, holotype [MNHU]: A. Habitus, dorso-lateral view; B. Terminal abdominal segments seen laterally; C. Head and prothorax seen laterally.