Nesiophasma Gunther 1934
Creators: name: Hennemann, Frank H.
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Phasmida
Phasmatidae
Nesiophasma

description: Genus Nesiophasma Günther, 1934
(Figs. 40–47)
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. 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 6 b.
Mylothrus Günther, 1935b: 18. [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): 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:
description: Published as part of 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), pp. 1-189 in Zootaxa 5073 (1) on pages 103-105, DOI: 10.11646/zootaxa.5073.1.1, http://zenodo.org/record/5760636