Hemiplasta rostrata (Redtenbacher, 1908), 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 : 143-144

Hemiplasta rostrata (Redtenbacher, 1908) rev. stat.

( Fig. 57 )

Sipyloidea (Hemiplasta) rostrata Redtenbacher, 1908: 550 . LT (by present designation), ♀: Minabassa, Staudinger; Siyploidea rostrata Br. ; Sintipo; MNCN Cat. Tipos N° 7352 [MNCN]. (Not: PLT, ♀: Sula Mangoli, Oct.–Novbr. Doherty, ex coll. H. Fruhstorfer ; det. Redtenb. Sipyloidea rostrata ; Sipyloidea rostrata R.; 22505 [NHMW, No. 1090] → this is H. styligera ( Bates, 1865)) Günther, 1934: 86 . [Synonymised with H. styligera ( Bates, 1865) in error]

Sipyloidea rostrata, Bruner, 1915: 238 .

Hemiplasta rostrata, Hennemann, 1998: 121 . [As a synonym of H. styligera ( Bates, 1865) ]

Otte & Brock, 2005: 153 [As a synonym of H. styligera ( Bates, 1865) ]

Differential diagnosis: The strongly elongated and filiform cerci of ♀♀ of this species ( Fig. 57C ) are shared with H. mustea ( Bates, 1865) n. comb. from the Sula and Banggai Islands and the Sulawesian H. nigra ( Hennemann, 1998) n. comb.. This species however readily differs from both these species by the notably more slender and elongate shape, much longer alae which reach as far back as abdominal tergum VIII (only reaching to tergum VI in mustea and nigra ), just very weakly and sparsely granulose mesonotum and yellow spots of the tegmina and costal region of the alae. From H. styligera ( Bates, 1865) , with which H. rostrata was synonymised in error (see comments below), ♀♀ readily differ by the smaller size, more stocky habitus and the long, filiform cerci.

Description: The following description is based on the unique lectotype. The specimen is in fairly good condition and complete except for lacking the right front leg and left antenna.

♀ ( Figs. 57A–B ). Medium-sized (body length including subgenital plate 73.0 mm) and fairly slender for the genus with very long alae (41.5 mm) that reach as far back as abdominal tergum VIII and long, filiform cerci. General colour of body and legs ochre to yellowish pale brown irregularly marbled with mid brown; ventral body surface generally lighter than dorsal surface. Head with faint mid brown and yellow longitudinal streaks and mesonotum with a pair of faint elongate, diverging yellow markings medially and a yellow marked mediolongitudinal carina. Eyes with a dark median ocular stripe. Antennae drab with every other antennomere black at the apex. Tegmina and costal region of alae chestnut brown with the radius yellow and with roundish yellow spots along all major longitudinal veins. Anal fan hyaline.

Head: Subrectangular, slightly longer than wide with the genae roughly parallel-sided and the vertex fairly flattened; smooth. No ocelli. Eyes slightly oval in outline, moderately projecting and their diameter contained about 2x in that of genae. Antennae reaching to abdominal segment V.

Thorax: Pronotum about as long but slightly narrower than head, rectangular in outline and about 1.3x longer than wide; the later margins gently concave in the median portion. Transverse median sulcus somewhat displaced towards the anterior, almost straight and expanding over entire width of segment.Anterior and posterior margin with black median spot. Mesothorax elongate and about 3.5x longer than pronotum; very slightly widened posteriorly. Mesonotum with a prominent and fairly acute longitudinal median carina and sparsely granulose on both sides of the carina ( Fig. 57B ); the lateral portions almost smooth buth with a fairly distinct carina paralled to lateral margins. Meso- and metapleurae as well as meso- and metasternum smooth. Tegmina elliptical in outline and unly with a shallow and obtuse central hump, that is very slightly displaced towards the posterior; the posterior margin very weakly angular. Alae very long, covering almost the entire abdomen and reaching to posterior margin of abdominal tergum VIII.

Abdomen: Abdomen excluding median segment and subgenital plate almost 2x longer than head, pro- and mesothorax combined; entirely smooth. Segments II–VII gradually decreasing in length with VII just a little more than half the length of II and hardly longer than wide; other notably longer than wide and roughly uniform in width. Preopercular organ on sternum VII formed by a blunt median swelling some distance off the posterior margin ( Fig. 57C ); the interveining portion carinate longitudinally. Tergum VIII and IX roughly equal in length and weakly narrowing, slightly shorter and narrower than VII. Anal segment almost 1.2x longer than IX, declining and gradually narrowing towards the posterior with the apex narrow and very deeply incised to form two slender, acute points. Epiproct small, triangular and not reachint apical tips of anal segment. Cerci very elongate, slender, cylindrical and filiform; 1.7x longer than anal segment and almost reaching to tip of subgenital plate ( Fig. 57C ); the basal portion very weakly curved and constricted. Subgenital plate as typical for the genus, being strongly keeled longitudinally, gently up-curving and having the lateral margins expanded anteriorly tor form an almust closed sword-like structure; apex acutely pointed and subgenital plate projecting beyond apex of abdomen by almost 2x the length of anal segment.

Legs: All long, slender and smooth. Profemora somewhat longer than head, pro- and mesothrax combined, metafemora slightly projecting over posterior margin of abdominal segment IV and metatibiae roughly reaching tip of anal segment. Basitarsi elongate, the probasitarsus notably longer than all following tarsomeres combined.

Comments: Redtenbacher (1908. 550) originally described H. rostrata from two ♀ syntypes, which however represent two distinct species. The foremost mentioned ♀ from Minhasa, Northern Sulawesi in MNCN is here se-lected as the lectotype to guarantee stability of the taxon. The second specimen from Pulau Mangole, Sula Islands in NHMW is a different species. Examination of both specimens has shown the latter one to be conspecific with H. styligera ( Bates, 1865) and based on this latter specimen Günther (1934: 86) synonymised Redtenbacher’s species. However, since the ♀ lectotype in MNCN is a distinct species, H. rostrata is here re-established as a valid species (rev. Stat.). The lectotype has as yet remained the only known specimen of H. rostrata and is here redescribed and illustrated. Male and egg unknown.

Distribution: N-Sulawesi, Prov. Sulawesi Utara (Minahasa).

Figures

FIGURE 57. Hemiplasta rostrata (Redtenbacher, 1908) rev. stat. ♂, lectotype [MNCN]: A. Habitus, lateral view; B. Habitus, dorsal view; C. Terminal abdominal segment in lateral aspect.