Necroscia malleoformia, 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 : 150-152

Necroscia malleoformia n. sp.

( Fig. 60 )

HT, ♂: S-Sulawesi, Selatan Prov. , Tana Toraja, leg. Tajuddin X.1995 – II.1996 [ MNHU, ex coll. FH] .

PT, ♂: S-Sulawesi, Selatan Prov. , Tana Toraja, leg. Tajuddin X.1995 – II.1996 [coll. FH, No. 1273-1] .

Etymology: The name (malleus, malleos lat. = hammer) refers to the prominently swollen and hammer-like tip of the abdomen of ♂♂ of this distinctive new species ( Figs. 60C–D ).

Differential diagnosis: The morphology of the terminalia of ♂♂ of this new species strongly resembles the Bornean Scionecra clavigera (Redtenbacher, 1908) , a species originally described in the genus Aruanoidea Redtenbacher, 1908 and now a synonym of Necroscia . This species is however misplaced in Scionecra Karny, 1923 why N. malleoformia n. sp. is provisionally assigned to Necroscia . The distinct genital morphology readily distinguishes it from clavigera and all Sulawesian members of Necroscia , which includes a strongly swollen abdominal tergum IX, enlarged and strongly tectiform anal segment, that is much higher than long as well as a flattened and spatulate subgenital plate.

Description: ♂ ( Figs. 60A–B ). Of average size for the genus (body length 61.0 mm), fairly typical in shape and general appearance, with well developed alae (34.0–35.0 mm) and a characteristically swollen and hammerlike apex of the abdomen. General colour straw to pale beige in the holotype (the paratype somewhat darker) with a very slight greenish wash along lateral margins of abdominal terga and bases of femora. Head with a fine mediolongitudinal black stripe on frons that continues about the the centre of the vertex and a washed brown postocular streak on cheeks. Eyes creamish mid brown. A fine black longitudinal line near lateral margins in the anterior half of mesonotum. Pro-, meso- and metasternum with a broad blackish medio-longitudinal streak, which gradually fades on metasternum. Tegmina chestnut brown with all longitudinal veins dark yellow and the radial vein marked by a bold yellow streak. Costal region of alae ochre with some irregularly dispersed and faint yellow spots and with the same yellow veins as in tegmina; anal fan hyalinous with slightly rosy longitudinal veins. Limbs coloured like body but the apical portion of all femora ochre to slightly reddish.Antennae brown and very weakly annulated with ochre, the four basal antennomeres black ventrally.

Head ( Fig. 60E ): Roundly rectangular, about 1.2x longer than wide, slightly flattened and the genae parallelsided; vertex smooth, flat with a fine coronal line and a C-shaped transverse impression in centre where the black stripe of the frons terminates. Area between the eyes slightly raised and very minutely but densely granulose. No ocelli. Eyes large, slightly oval in outline and their length contained about 1.2x in length of genae. Antennae almost reaching to tip of abdomen. Scapus somewhat flattened, rectangular in outline and 1.3x longer than wide. Pedicellus ovate, round in cross-section and slightly shorter than scapus, antennomere III roughly equal in length and constricted towards apex.

Thorax: Pronotum slightly narrower but about equal in length to head, the anterior portion somewhat deflexed and the angles with a semi-circular excavation, remainder of segment parallel-sided; 1.25x longer than wide. A distinct pit is seen near the anterolateral angles, the remainder of the surface with a slightly impressed medio-longitudinal line; the transverse median sulcus prominent and broad in the median portion but narrow in the lateral portion, straight and expanding over entire width of segment ( Fig. 60E ). Mesothorax elongate, 3.75x longer than pronotum and very gently widened in the posterior one third. Mesonotum unevenly rugulose ( Fig. 60E ) with the rugulae gradually becoming less pronounced towards the posterior and with a fine longitudinal median carina; a transverse bulge near anterior margin. Mesopleurae very weakly and sparsely rugulose, mesosternum, metapleurae and metasternum smooth. Tegmina oval, scale-like and just with a small and obtuse pre-median hump. Alae reaching to posterior margin of abdominal tergum VI.

Abdomen: Median segment considerably longer than metanotum. Segments II–V roughly uniform in length and width and about 4x longer than wide. VI–VII decreasing in length with VII three-quarters the length of V. Tergum VII with lateral margins slightly widening towards the posterior, the posterolateral angles somewhat deflexed triangularly. Sterna V–VII weakly tectinate longitudinally. Tergum VIII shortest segment and three-quarters the length of VII, the posterior margin concave and connected to tergum IX by a large membranous area that allows the folding up of the terminal two segments. Tergum IX notably longer than VIII, as long as high with the dorsal surface slightly gibbose and the lateral surfaces roundly swollen. Anal segment much short-er than IX, strongly and acutely tectinate, almost 2x higher than long ( Fig. 60C ) with the posterolateral angles protroded into an obtusely triangular projection that is somewhat concave interiorly and set with a few minute denticles ( Fig. 60D ). Epiproct very small and almost completely concealed by anal segment. Cerci rather small but elongate, round in cross-section gently in-curved and with the apex slightly club-like; downward directed. Vomer slender and with a single, gently up-curving terminal hook. Poculum slender, flat and weakly tectiform longitudinally with the apex obtusely rounded; almost reaching to posterior margin of tergum IX ( Fig. 60D ).

Legs: All long, slender, just weakly carinated and unarmed. Profemora notably longer than head, pro- and mesothorax combined with the base strongly constricted and distinctly curved. Mesofemora longer than mesothorax and metafemora slightly projecting over posterior margin of abdominal segment IV; medioventral carina obtuse and indistinct. All basitarsi slender, pro- and metabasitarsus about as long as remaining tarsomeres combined, mesobasitarsus slightly shorter than combined length of remaining tarsomeres.

Comments: This species is here placed in Necroscia Serville, 1838 with reservation. The distinctive morphology of the terminalia most strongly resembles certain members of this genus, which however is a polyphyletic grouping and certainly deserves splitting in the future. With no ♂♂ of the genus Hemiplasta Redtenbacher, 1908 identified at that time, Hennemann (1998: 113, fig. 19, pl. 3: 6–7) believed this species to represent the ♂♂ of Hemiplasta styligera ( Bates, 1865) and provided a description and illustrations. Availability of the true ♂♂ of H. styligera and knowledge of the ♂♂ of several Hemiplasta -species however has shown the concerned two specimens two represent an as yet undescribed and not congeneric species. Female and egg unknown.

Distribution: South Sulawesi, Prov. Sulawesi Selatan, Tana Toraja.

Figures

FIGURE 60. Necroscia malleoformia n. sp. ♂, holotype [MNHU]: A. Habitus, lateral view; B. Habitus dorso-lateral view; C. Terminal abdominal segments in lateral aspect; D. Terminal two abdominal segments seen ventrally; E. Head, pro- and mesothorax in dorso-lateral aspect.