Periphetes borealis, 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 : 66-67

Periphetes borealis n. sp.

( Fig. 27 )

Phasgania furcata, Günther, 1938: 74 , fig. 14 (§).

Carausius furcatus, Hennemann, 1998: 118 .

Periphetes sp. , Hennemann & Conle, 2007: 53.

HT, ♂: Sarasin, IX.1894, Masarang-Kette, Nord-Celebes; Phasgania furcata Br. v. W. K. Günther det. [ NHMB] .

PT, ♂: Malawù Gipfel. Celebes, 25. VII . 94. Sar.; Phasgania furcata Br. v. W. K. Günther det. [ NHMB] .

Etymology: The name ( borealis lat. = northern) refers to the distribution of this new species in the very northeastern part of Sulawesi.

Differential diagnosis: Males of this new species (the only sex known) are very similar to P. parastatidon Günther, 1935 , but differ by the considerably more slender form and relatively longer body segments, more roughly granulose head, smaller pair of spines between the eyes ( Fig. 27D ) and much shorter processes of the anal segment (figs. 27F–G).

Description. The colouration is described from the paratype only, because the holotype is discoloured to yellowish brown by provisional storage in spirits ( Figs. 27A–B ).

♂ ( Figs. 27A–B ). Fairly small for the genus (body length 55.0– 57.5 mm), shape moderately slender. As typical for the genus, the entire body surface densely granulose. Entire dorsal body surface with a very weakly indicated longitudinal keel. General colour olive green, head and basal portion of profemora dark green, most of prothorax, posterior portion of meso- and metathorax as well as portions of abdominal segments VIII, IX and poculum dark ochre to brown. Apices of femora washed black and apical portion of tibiae mid brown. Scapus and pedicellus very dark green with a slight blackish wash, rest of antennae very dark reddish brown. Eyes reddish brown .

Head: Ovoid, about 1.4x longer than wide, broadest just behind the eyes ( Fig. 27C ) and vertex rather flat ( Fig. 27D ). Entire surface granulose and with a pair of fairly short but acutely pointed and anteriad directed spines between the eyes ( Fig. 27D ). Granules in the interocular portion more rough than elsewhere. Eyes circular in outline and projecting hemispherically, their length contained 2x in that of genae. Antennae long, filiform and roughly reaching to abdominal segment II. Scapus compressed dorsoventrally, slighly narrowed towards the base and 2x longer than wide ( Fig. 27C . Pedicellus round in cross-section and slightly constricted towards apex.

Thorax: Pronotum slightly shorter and narrower than head, the anterior portion a little broader than posterior portion, the transverse median sulcus prominent, gently curved and expanding over entire segment ( Figs. 27C–D ). Anterior margin with a transverse row of tubercles and two clusters of enlarged tubercles medially. Mesothorax slender and elongate, 5.5x longer than pronotum and notably widened in posterior portion. Metanotum a little less than 2/3 the length of mesonotum, gently widened medially and with posterior portion widened. Meso- and metanotum with posterior margin slightly, obtusely swollen.

Abdomen: Median segment slightly less than ¼ the length of metanotum. Abdomen excluding median segment somewhat less than complete thorax. Segment II about 2x longer than median segment, II–VI almost uniform in length and width, VII slightly shorter; II–VI on average 2.2x longer than wide. TergaVIII and IX acutely keeled longitudinally, VIII trapezoidal with posterior margin 1.8x wider than anterior margin and about 3/5 the length of VII. IX shorter than VIII and notably narrowing towards posterior. Anal segment strongly tectiform split to form two movable hemi-terga, which have the lower angle protruded into a narrow, in-curving hook-like process that terminates in an acutely pointed inward directed spine; the interior surfaces with 1–2 smaller teeth ( Fig. 27G, H ) and the lateral outer surface with an obtuse longitudinal keel. Epiproct very small and not visible in dorsal aspect. Cerci very small, slender and somewhat compressed laterally at the base. Poculum fairly large, roundly cup-shaped with the posterior margin broadly rounded ( Fig. 27H ) and the surface minutely rugulose, slightly projecting over posterior margin of tergum IX ( Figs. 27E–F ).

Legs: Moderately long, the meso- and metafemora somewhat swollen and thickened with their base narrowed. All carinae minutely granulose. Profemora with a distinct, curved, black tipped sub-apical spine on medioventral carina. Meso- and metafemora with a fairly prominent and acute, triangular sub-apical tooth on both outer ventral carinae. Medioventral carina of meso- and metafemora moderately distinct and like all other carinae marked by a longitudinal row of minute granules. Basitarsi slender and longer than following three tarsomeres combined.

Comments: These two ♂♂ have been briefly described by Günther (1938: 74), who misidentified them as Phasgania furcata (Brunner v. Wattenwyl, 1907). Examination has readily shown that they represent another as yet undescribed species. Females and eggs unknown.

Distribution: NE-Sulawesi, Province Sulawesi Utara, Minahasa, Masarang Mountains & Mount Mahawu, summit ca. 1300 m [NHMB].

Figures

FIGURE 27. Periphetes borealis n. sp. ♂♂ [NHMB]: A. HT, dorsal view; B. HT, lateral view; C. Head and prothorax of HT in dorsal aspect; D. Dorso-lateral view of head and prothorax of PT; E. Terminal abdominal segments of PT in lateral view; F. Terminal abdominal segments of HT in lateral view; G. Terminal abdominal segments of HT in dorsal view; H. Terminal abdominal segments of PT in ventral view. Figures A–C, F, G © 2019 Natural History Museum Basel, Switzerland, S. Klopfstein.