Stephanacridini Günther, 1953

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 : 103-106

publication ID	https://doi.org/ 10.11646/zootaxa.5073.1.1
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scientific name	Stephanacridini Günther, 1953
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Tribe Stephanacridini Günther, 1953 View in CoL

Genus Nesiophasma Günther, 1934

( Figs. 40–47 View FIGURE 40 View FIGURE 41 View FIGURE 42 View FIGURE 43 View FIGURE 44 View FIGURE 45 View FIGURE 46 View FIGURE 47 )

Type-species: Nesiophasma eremothocus Günther, 1934: 5 [= Myronides spinulosus Brunner v. Wattenwyl, 1907: 254], by original designation of Günther, 1934: 5.

Nesiophasma Günther, 1934: 5 View in CoL .

Günther, 1935a: 139.

Günther, 1935b: 29.

Günther, 1953: 555.

Bradley & Galil, 1977: 193.

Hennemann, 1998: 124.

Zompro, 2004: 314.

Otte & Brock, 2005: 227.

Hennemann & Conle, 2008: 57, Fig. 60a View FIGURE 60 6 b View FIGURE 6 .

Mylothrus Günther, 1935b: 18 View in CoL . [Synonymised by Günther, 1935b: 29 (Nachtrag 3)]

Günther, 1934b: 78.

Description: ♀, ♂. Medium to very large (body length ♂♂ 76.0– 186.5 mm, ♀♀ incl. subgenital plate 174.0–301.0 mm), slender and elongate, fully apterous Stephanacridini . Body smooth and unarmed, often slightly shiny in ♂♂; rarely with a few small granules on mesopleurae in ♀♀. Sexual dimorphism strongly developed with ♂♂ much shorter and very much more slender than ♀♀. Head ovoid, longer than wide with vertex gently convex and smooth. No ocelli. Gula a ± rectangular plate that expands considerably less than 1/3 of cervical membrane. Antennae moderately long and filiform, laid back at least reaching to metanotum or projecting as far back as abdominal segment V; comparatively longer in ♂♂. Mesothorax> 2x longer than head and pronotum combined; comparatively longer in ♂♂. In ♀♀ ± distinctly swollen pre-medially, in ♂♂ very slender and parallel-sided. Meso- and metasternum gently tectiform longitudinally or with a weak longitudinal median keel (less defined on metasternum). Median segment short, less than ½ the length of metanotum. Abdomen excluding median segment notably longer than combined length of head and complete thorax. Abdominal segments II–VII slender, parallel-sided and considerably longer than wide in ♂♂; longer than wide in ♀♀ but sometimes gently broadened medially (only two species with lateral margins roundly expanded to form lobes). Abdominal sterna II–VI smooth; VII in ♀♀ with a moderate Preopercular that is represented by one or two granules or spiniform tubercles some distance off the posterior margin. Terminalia of ♀♀: Anal segment of a very typical shape, having the lateral margins strongly excavated near the bases of the cerci and the posterior margin with a deep and narrow median incision; the two portion on each side of the median incision forming a ± rounded to obtusely angular lobe. Cerci small and conical with a pointed tip. Epiproct small, mostly hidden under anal segment. Gonapophysis VIII elongated and often projecting considerably beyond anal segment; inner surface often with a deep longitudinal furrow. Subgenital plate long and lanceolate, projecting beyond apex of abdomen by more than length of anal segment. Terminalia of ♂♂: Anal segment simple, gently tectiform with the posterior margin ± excavated and the outer lateral angles ± obtuse and/or expanded and set with a variable number of small denticles ventrally. Epiproct very small and fully hidden under anal segment. Vomer a strongly sclerotised, ± triangular plate with a single, up-curving terminal hook. Cerci small and round in cross-section. Poculum fairly small, cup-like and not projecting over posterior margin of tergum IX. Legs all long and slender with all carinae to a variable degree dentate and/or serrate. Base of profemora strongly compressed and curved. Medioventral carina of profemora indistinct and midways on ventral surface of profemur; of meso- and metafemora moderate and either smooth are sparsely set with small spines. Tarsi long, probasitarsus longer than remaining tarsomeres combined; meso- and metabasitarsus longer than combined length of following three tarsomeres with all carinae ± dentate. Basitarsi sometimes with dorsal carinae gently raised and rounded.

Egg ( Fig. 47 View FIGURE 47 ): Medium to large, capsule notably longer than wide or high; ± strongly laterally compressed and with an obtuse ± prominent longitudinal bulge or keel surrounding egg-capsule except for impressed polar-area and region around micropylar plate. Capsule surface sculptured, ranging from coriaceous to being all over covered with irregularly raised ridges and bulges. Micropylar plate small, less than 1/3 the length of capsule and positioned roughly in centre of dorsal egg surface; rhomboidal to spear-shaped. Median line distinct. Operculum oval and flat, in centre with an irregularly shaped and strongly sculptured ± conical capitulum.

Differential diagnosis: Morphologically very similar and most likely very closely related to Sadyattes Stål, 1875 (Type-species: Sadyattes borrii Stål, 1875 ) and Eucarcharus Brunner v. Wattenwyl, 1907 (Type-species: Lonchodes feruloides Westwood, 1859 ). Both genera are however geographically restricted to the Oriental region west of the Wallace Line and the Philippines. In contrast to Nesiophasma both genera have a comparatively longer median segment in both sexes, that is longer than the median segment, and ♂♂ are winged. In all other aspects morphological differences are hard to define and thus it is hoped that molecular data will sometime clarify whether Nesiophasma can reliably be separated from these two genera on a generic basis.

Comments: The tribe Stephanacridini Günther, 1953 was partly redefined and reorganized by Hennemann & Conle (2008: 54), who transferred several genera that were previously attributed to the tribe Pharnaciini . Currently, Stephanacridini contains eight genera that are mostly distributed throughout Wallacea, New Guinea and Melanesia with only a few representatives in the Philippines and Sundaland. The type-genus Stephanacris Redtenbacher, 1908 was re-described by Hennemann & Conle (2006b) and the genus Macrophasma Hennemann & Conle, 2006 was established to comprise the New Guinean species formerly placed in the principally Melanesian Hermarchus Stål, 1875 . Phasmotaenia Návas, 1907 was removed from Pharnaciini and transferred to Stephanacridini by Hennemann & Conle (2008: 57) and a revision of the genus was presented subsequently (Hennemann & Conle, 2009). The monotypical Diagoras Stål, 1875 is only known from the ♀♀ and endemic to the Palau Islands. The three remaining genera deserve a more comprehensive treatment.

Nesiophasma Günther, 1934 comprises median to very large exclusively apterous species that are mostly distributed throughout Wallacea. Only one species has been described from New Guinea, but this record must be regarded as doubtful and deserves confirmation by fresh material of the concerned species. Most of the species are very rarely encountered and the eggs have previously been unknown. Recent collections on the islands of Peleng (Banggai Islands) and Sanana (Sula Islands) have revealed two gigantic as yet unrecognised species that are described herein. These two new species and the fact that the author had in manuscript an unfinished revision of Nesiophasma , that was originally compiled in the course of the revision of Pharnaciini sensu Günther, 1953 (Hennemann & Conle, 2008), seemed like reason enough to present a review of Nesiophasma herein.

As mentioned above the morphologically most similar and presumably most closely related genera are Sadyattes Stål, 1875 and Eucarcharus Brunner v. Wattenwyl, 1907. The species currently attributed to either Sadyattes or Eucarcharus are very similar in almost all aspects and suggest these two genera are likely to be synonymous. Both are paraphyletic in their present recognition and Sadyattes even is polyphyletic because it has recently been enriched by a species that definitely belongs in the tribe Pharnaciini . The tribes Pharnaciini (subfamily Clitumninae ) and Stephanacridini (subfamily Platycraninae ) have been clearly separated by obvious morphological characters that differ fundamentally between these two clades by Hennemann & Conle (2008: 60, table 1) and this distinction is moreover well supported an in accordance to phylogenetic approaches based on morphological data ( Buckley et al., 2010) and molecular data ( Robertson et al., 2018). In aspect of this morphologically very obvious and well supported distinction between these two not closely related clades, it is very questionable why Seow-Choen (2017: 151) removed the well-known Phobaeticus chani (Bragg, 2008) from the tribe Pharnaciini and erroneously transferred it to Sadyattes (tribe Stephanacridini ). Males of Phobaeticus chani have an anal segment that is longitudinally split into two hemiterga and lack a vomer, ♀♀ have a fairly prominent Preopercular organ, both sexes have the medioventral carina of the profemora distinctly displaced towards the anteroventral carina and eggs have an open internal micropylar plate and s well as a stalked capitulum. All these key features more than clearly place Ph. chani in the tribe Pharnaciini (subfamily Clitumninae ) and the egg morphology in particular justifies the original taxonomic position within the genus Phobaeticus Brunner v. Wattenwyl, 1907. In the tribe Stephanacridini (subfamily Platycraninae ), to which the genus Sadyattes belongs (Hennemann & Conle, 2008; Hennemann, 2020), ♂♂ have a simple anal segment and a well developed vomer, ♀♀ merely have an indistinct Preopercular organ and extremely elongated, filiform go-napophysis VIII, that project considerably beyond the apex of the abdomen, and both sexes have profemora that are trapezoidal in cross-section with the rather indistinct medioventral roughly midways on the ventral surface of the femur. All of theses key features of Stephanacridini are not true for Phobaeticus chani (Bragg, 2008) and therefore this species is here transferred back to its original genus (rev. comb.).

Distribution: Sulawesi, Peleng Island, Selayar Island, Kalaotoa Island, Sanana Island, Romang Island, Sangihe Island and Talaud Islands. New Guinea with doubt.

Species included:

1. Nesiophasma giganteum n. sp.

Distribution: Banggai Islands (Peleng).

2. Nesiophasma kuehni (Brunner v. Wattenwyl, 1907: 185).

Distribution: Pulau Romang.

3. Nesiophasma oligarches ( Günther, 1935a: 18, pl. 2: 12).

Distribution: S-Sulawesi.

4. Nesiophasma plateni ( Dohrn, 1910: 404) .

Distribution: Sangihe Islands & Talaud Islands.

5. Nesiophasma sananaense n. sp.

Distribution: Sula Islands (Sanana Island).

6. Nesiophasma spinulosum (Brunner v. Wattenwyl, 1907: 254).

= Nesiophasma eremothocus Günther, 1934a: 6 View in CoL , fig. 1.

Distribution: Pulau Selayar & Pulau Kalaotoa.

7. Nesiophasma turbans (Brunner v. Wattenwyl, 1907: 186).

Distribution: Sulawesi.

8. Nesiophasma zanum Hennemann, 1999: 213 , figs. 1–2.

Distribution: New Guinea (? - see comments below).

Keys to the species of Nesiophasma View in CoL

♀♀ *

1. Abdominal terga II–VI with lateral margins at best gently rounded.............................................. 2

- Abdominal terga II–VI strongly laterally deflexed and convex ( Fig. 43D View FIGURE 43 ); Pulau Romang........................ kuehni View in CoL

2. Gonapophysis VIII short and not projecting over posterior margin of anal segment................................. 3

- Gonapophysis VIII long and notably projecting over posterior margin of anal segment.............................. 4

3. Small species (body length incl. subgenital plate <180.0 mm); median segment> 2/3 the length of metanotum; abdominal terga VII–IX with slender posteriad-directed posterolateral lobe; subgenital plate short and only slightly projecting over apex of abdomen; New Guinea (?)........................................................................ zanum View in CoL

- Very large species (body length incl. subgenital plate> 250.0 mm); median segment only ¼ the length of metanotum ( Figs. 43A–B View FIGURE 43 ); abdominal terga VII–IX not lobed; subgenital plate very long, lanceolate and projecting over apex of abdomen by more than combined length of terga VIII–X ( Figs. 45P–R View FIGURE 45 ); Sangihe & Talaud Islands........................... plateni View in CoL

4. Slender and very elongate insects; mesonotum at least 4.5x longer than wide; basitarsi slender........................ 5

- More stocky ( Fig. 43C View FIGURE 43 ); mesonotum 4x longer than wide and expanded pre-medially; basitarsi with dorsal carinae raised and rounded; Pulau Selayar & Pulau Kalaotoa.......................................................... spinulosum View in CoL

5. Mesonotum 6x longer than wide and slender ( Figs. 40D–F View FIGURE 40 ); antennae reaching to median segment; Pulau Sanana (Sula Islands)................................................................................. sananaense View in CoL n. sp.

- Mesonotum 4.5x longer than wide and gently swollen pre-medially ( Figs. 40A–C View FIGURE 40 ); antennae reaching to abdominal segment II; Peleng (Banggai Islands)................................................................... giganteum View in CoL n. sp.

* ♀♀ of N. oligarches (Günther) View in CoL and N. turbans View in CoL (Brunner v.Wattenwyl, 1907) are not known

♂♂ *

1. Body length> 100.0 mm; abdominal terga II–VI> 3x longer than wide.......................................... 2

- Smaller; abdominal terga II–VI 2.5x longer than wide; Sulawesi ( Fig. 44D View FIGURE 44 )................................ oligarches View in CoL

2. Head and pronotum of same colour as remainder parts of body; body ± uniform in colour............................ 3

- Head and pronotum contrasting blackish; dark streak along entire lateral surfaces of body; Pulau Selayar & Pulau Kalaotoa............................................................................................. spinulosum View in CoL

3. Body length <160.0 mm; colouration more or less uniform.................................................... 4

- Body length> 160.0 mm; bases of all femora and knees contrasting black; Sangihe Islands & Talaud Isalnds......... plateni View in CoL

4. Very slender species ( Fig. 44A View FIGURE 44 ); median segment very short and only 1/6 the length of metanotum; Sulawesi ....... turbans View in CoL

- More stocky ( Figs. 44B–C View FIGURE 44 ); median segment <1/3 the length of metanotum; Peleng.................... giganteum View in CoL n. sp.

* ♂♂ of N. kuehni View in CoL (Brunner v.Wattenwyl, 1907), N. zanum Hennemann, 1999 View in CoL and N. sananaense View in CoL n. sp. are not known