Hemiplasta nigra ( Hennemann, 1998 ) 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 : 137-141

Hemiplasta nigra ( Hennemann, 1998) n. comb.

( Figs. 54–55 )

Nescicroa nigra Hennemann, 1998: 550 . HT, ♂: 7921; Holotypus; Nescicroa nigra Hennemann n. sp. ♂, det. F. Hennemann IV. 1996; S-Sulawesi (Tana Toraja), Rantepao 700 m, leg. Tajuddin 10.95–3.96 [MNHU, No. 7921]. PT, 2 ♂♂: Indonesien: S-Sulawesi, Tana Toraja, Rantepao, 700 m, leg. Tajuddin X.1996 – III.1996 [coll. FH, No’s 0289-1 & 2].

Otte & Brock, 2005: 225.

Zompro, 2005: 273. (Catalogued)

Hemiplasta falcata, Hennemann, 1998: 115 , fig. 20, pl. 3: 1 (in part—only the illlustrated specimen from Sulawesi)

Further material: 1 ♀: Indonesien, S-Sulawesi, Tana Toraja , Highland c. 800 m, leg. Tajuddin X.1995 – III.1996 [coll. FH, No. 0289-3] .

Differential diagnosis: Very similar to H. mustea ( Bates, 1865) n. comb. with which ♀♀ share the fairly stocky shape, fairly shortened alae and strongly elongated cerci ( Figs. 54D–F ). Females however readily differ from those of H. mustea by the dark brown general colour and faint yellowish to pale green spots of the tegmina and costal region of the alae. Morphologically they can be distinguished from H. mustea by the notably more pronounced and acute granules and more distinct medio-longitudinal carina of the mesonotum ( Fig. 54C ), relatively shorter mesothorax which is only about 3.9x longer than the prothorax (5x longer in mustea ), and differently shaped anal segment, which is somewhat more slender with the posterolateral angles more obtuse and broader than in mustea (fig. 54E). Males differ from those of H. mustea by the dull brown the blackish general colour ( Fig. 55A ), plain brown tegmina and costal region of the alae, less distinctly annulated legs, slightly shorter and more prominently granulose mesonotum ( Fig. 55F ), which has the medio-longitudinal carina notably more pronounced and acute, wider and more shallow posteromedian excavation of the anal segment ( Fig. 55C ) and more narrowed posterior margin of the poculum ( Fig. 55D ).

Description: The following descriptions are based on the unique known ♀ and the three ♂ types specimens.

♀ ( Figs. 54A–B ): Medium-sized (boy length incl. subgenital plate 71.0 mm), form stocky for the genus, with moderately long alae (31.5 mm) that reach to abdominal segment VI and very long, filiform cerci. General colour of the unique specimen mid brown with a slight greenish wash on the head, pronotum, tegmina and costal region the alae. Abdominal tergum VIII with a central pair of roundish, washed dark brown markings. Granulation of the pro- and mesonotum yellow to ochre. Basal quarter of antennae annulated with dull ochre and brown; pedicellus black. Tegmina with three very pale creamish green spots just in front of the radius, otherwise with a few very faint green speckles and the portion anterior to the radius more greenish than the posterior portion. Costal region of alae weakly and unevenly flecked with pale green in the portion anterior to the radius; the radius itself unevenly marked by dark brown spots. Anal region of alae translucent grey with all radial veins weakly marked by some darker spots. Meso- and metatibiae with three faint dull ochre transverse bands .

Head: Subquadrate in dorsal aspect, slightly longer than wide with the genae almost parallel-sided and the vertex smooth and very weakly convex ( Fig. 54C ). Two very low raised areas between the eyes, a small V-shaped median impression on frons and a slightly impressed coronal line on vertex. No ocelli. Eyes strongly projecting, slightly ovoid in outline and their length contained about 1.6x in that of genae ( Fig. 54C ). Scapus compressed dorsoventrally, 1.3x longer than wide, pedicellus shorter and slightly oval in cross-section and antennomere III somewhat longer than pedicellus. Antennae reaching to abdominal segment VIII.

Thorax: Pronotum about as long but notably narrower than head and slightly gradually narrowing towards the posterior; the lateral margins very weakly concave ( Fig. 54C ). Median line impressed almost over entire length of segment, the transverse median sulcus almost straight and not reaching to lateral margins. Surface minutely and unevenly granulose. Mesothorax 3.9 longer than pronotum, slightly constricted post-medially and widest about one quarter behind anterior margin. Mesonotum with a fine but distinct and acute longitudinal median carina and distinctly granulose ( Fig. 54C ); the granules close to the medio-longitudinal carina most pronounced and each bearing a single stiff bristle. Lateral surfaces of mesonotum with a granulose longitudinal carina parallel to lateral margins; the granules below more greenish in colour than the dorsal granulae. Mesosternum with an obtuse longitudinal median keel in anterior portion, otherwise granulose. Meso- and metaplaureae sparsely granulose. Tegmina ovoid in outline with the posterior margin weakly angular; the central hump very weakly developed. Alae reaching to posterior margin of abdominal segment VI.

Abdomen: Segment IV slightly shorter than median segment, 1,25 longer than wide and rectangular. III–VII slightly gradually decreasing in length, terga IV–VII somewhat expanded at posterior margin and VII slightly narrowed towards posterior and a little wider than long. All terga with a very pronounced, obtuse longitudinal lateral carina parallel to lateral margins. Preopercular organ on sternum VII formed by the raised and somewhat labiate and concave posterior margin and a shallow median swelling some distance in front of the margin ( Fig. 54F ). Tergum VIII somewhat longer than VII and obtusely tectinate longitudinally, the lateral margins slightly deflexed and rounded in posterior half; IX similar, about equal in length but lateral margins straight. Anal segment a little longer than two preceding terga, acutely tectinate longitudinally, strongly narrowed in the apical half and the posterior margin with a moderate, triangular incision with the outer angles obtusely triangular ( Fig. 54E ). Epiproct small, shieldshaped and wider than long with the posterior margin very widely rounded. Cerci very long, slender, cylindrical and almost 1.6x longer than anal segment ( Fig. 54D ). Subgenital plate as typical for the genus, gently up-curving and projecting beyond apex of abdomen by about the combined length of the two terminal terga; apex acutely pointed ( Fig. 54D ).

Legs: All moderately long and slender; entirely unarmed except for a blunt, tooth-like sub-apical swelling of the fairly pronounced medioventral carina of the femora. Profemora strongly curved basally and about as long as pro- and mesothorax combined, metafemora reaching to posterior margin of abdominal segment V and metatibiae projecting somewhat beyond anal segment. Basitarsi long, slender and longer than following three tarsomeres combined.

♂ ( Fig. 55 ). Of average size (body length 60.3–63.0 mm) and typical in shape for the genus, with a distinctly granulose mesonotum, plain coloured tegmina and costal region of the alae and bulgy three terminal abdominal segment. General colour dark brown with a slight greenish wash, some portion of a dull ochre hue. Granulations of the mesothorax mid brown to dull ochre. Tegmina and costal region of alae plain dark brown, the radius of the alae black; anal fan transparent grey. Basal portions of all femora dark greyish green, the apex blackish brown. Eyes greyish to reddish brown and with a faint dark longitudinal ocular streak in the dried specimens.

Head ( Fig. 55F ): Fairly large, ovoid, broadest at the eyes with the vertex gently convex, smooth; coronal line slightly impressed. Frons with a widely V-shaped impression and between eyes with a pair of weakly convex humps, that are of a slightly lighter colour than the head capsule. No ocelli. Eyes very large, projecting hemispherically, almost circular in outline and their diameter contained only about 1.1x in length of genae. Antennae somewhat longer than body. Scapus and pedicellus generally as in ♀♀, black.

Thorax: Pronotum generally as in ♀♀, about 1.5x longer than wide and somewhat narrower than head; granu-lation comparatively less pronounced. The transverse median sulcus notably displaced towards the anterior and almost reaching lateral margins of segment ( Fig. 55F ). Mesothorax 3.9x longer than prothorax. Mesonotum prominently and densely granulose and with a distinct medio-longitudinal carina; the granules most pronounced along the carina and a granulose longitudinal lateral carina close to lateral margins. Mesosternum very weakly tectinate longitudinally and moderately granulose. Meso- and metaplaeurae only with a few scattered granules. Mesosternum smooth. Tegmina ovoid in outline with the posterior margin very weakly and obtusely triangular interiorly, the central hump moderately developed and very obtusely conical.Alae reaching to posterior margin of abdominal segment VI to about half way along VII.

Abdomen: Segment II slightly shorter than median segment and as long as III, III–VII decreasing in length and VII only a little more than half the length of II and III; all longer than wide. II–VI uniform in width and cylindrical. VII very slightly widened posteriorly. Terminal three segments strongly swollen and together of a club-like appearance; IX almost 2x the width of VI. Tergum VIII trapezoidal in dorsal aspect with the posterior margin prominently excavated triangularly and much of the dorsal surface covered by a membrane that allows folding up the terminal two segments towards the anterior ( Fig. 55C ). Tergum IX with a similar but much smaller membranous area anteriorly; segment about 2x longer than VIII, the lateral margins notably deflexed and slightly in-curving posteriorly. Anal segment less than half the length of IX, slightly tectiform and triangular in lateral aspect with the lateral margin slightly deflexed into a blunt tooth-like projection medially; the posterior margin with a concave excavation ( Fig. 55C ) and the outer angles protruded into an obtusely rounded swelling that bears several small denticles intero-ventrally ( Fig. 55E ). Epiproct very small. Vomer roughly triangular in shape with a fairly short and strong, up-curving terminal hook; the ventral surface obtusely tectinate longitudinally. Cerci long, slender, very gently in-curving and with the apex blunt; about as long as anal segment ( Fig. 55B ). Phallus prominently elongated, forming a slender and tube-like organ that is bent towards the left and laterally projects notably over the lateral margin of the poculum. Sternum IX enlarged and very bulgy with the posterior margin convex and medially expanded towards the posterior. Poculum cup-shaped, angular and obtusely keeled longitudinally, the posterior margin somewhat labiate, narrowed and roundly angular, the lateral margins concave and excavated. ( Fig. 55B )

Legs: All long, slender and entirely unarmed. Profemora somewhat longer than pro- and mesothorax combined, metafemora reaching about half way along abdominal segment V and metatibiae roughly reaching to tip of abdomen. Tarsi all long and slender with the basitarsi longer than the following three tarsomeres combined.

Comments: Hennemann (1998: 108) originally described this species based on three ♂♂, all from Rantepao in the Tana Toraja highlands. The specimens figured ( Hennemann, 1998: 108, fig. 12) is not the holotype as stated in the corresponding legend of that publication but is one of the paratypes (coll. FH, No. 0298-2). Knowledge of the previously unknown ♂♂ of other Hemiplasta -species and careful re-examination of the type specimens has shown N. nigra to be a member of Hemiplasta (n. comb.). In addition to being very similar in all morphological aspects to the ♂♂ of H. mustea , which presumably is the closely related species, this is also seen in the genital morphology of ♂♂, which includes a very long and filiform phallus. Re-examination of the ♀ from the same locality, that Hennemann (1998: 115) regarded as a variety of H. falcata (= H. mustea ) has proven this to be a distinct species and the opposite sex of H. nigra . English re-descriptions of both sexes are here provided.

Distribution: Central Sulawesi (Tana Toraja).

Figures

FIGURE 54. Hemiplasta nigra (Hennemann, 1998) n. comb. ♀ [coll. FH, No. 0298-3]: A. Habitus, dorso-lateral view; B. Habitus, dorsal view; C. Head, pro- and mesothorax in dorso-lateral view; D. Terminal abdominal segments in lateral aspect E. Terminal abdominal segments in dorsal aspect; F. Terminal abdominal segments in ventral aspect.

FIGURE 55. Hemiplasta nigra (Hennemann, 1998) n. comb. ♂♂: A. habitus (PT), dorso-lateral view [coll. FH, No. 0298-1]; B. Terminal abdominal segments of ♂ (PT) in lateral aspect [coll. FH, No. 0298-2]; C. Terminal abdominal segments of ♂ (PT) in dorsal aspect [coll. FH, No. 0298-2]; D. Terminal abdominal segments of ♂ (PT) in ventral aspect [coll. FH, No. 0298-2]; E. Close up of terminal two abdominal segments of ♂ (PT) in ventral aspect [coll. FH, No. 0298-2]; F. Head, pro- and mesothorax of ♂ (PT) seen dorso-laterally [coll. FH, No. 0298-1].