Sadyattes tubaense, Hennemann, 2025

Hennemann, Frank H., 2025, A review of Sadyattes Stål, 1875, with the descriptions of six new species from the Philippines (Phasmatodea: Platycraninae: Stephanacridini), Zootaxa 5610 (1), pp. 1-72 : 62-68

Sadyattes tubaense sp. nov.

ZooBank: https://zoobank.org/NomenclaturalActs/ B50FB764-9D0D-404C-B385-48FC0E3E2787

( Fig. 20 )

HT, ♂: Coll. I.R.Sc.N.B., Philippines, Luzon, Benguet, Tuba, Leg. T. Heitzmann [ RBINS] .

Differentiation. The ♂ of this new species (the only sex known) is easily distinguished from its Philippine congeneric by the inconspicuous dark green overall colouration and is smaller than the other two Luzonian S. fallax (Brunner v. Wattenwyl, 1907) and S. feruloides ( Westwood, 1859) . From the first it is easily separated by the more elongate and ovoid head, which is not as distinctly yellow as in fallax and lacks the characteristic black postocular streak seen in that species (only a faint and washed green postocular stripe in tubaense ; Figs. 20C–D ), lack of the distinct black posterior transverse band of abdominal segments II–VII seen in fallax (posterior portion only dark brown in tubaense ), just very weakly indicated annulations of the meso- and metatibiae (brown with three distinct yellow to orange annulae in fallax ), shorter poculum which does not reach to the posterior margin of abdominal tergum IX ( Fig. 20E ) and larger, more elongate vomer ( Fig. 20G ). From the much slenderer feruloides this ♂ is readily distinguished by lacking the black abdominal terga II-VI, black longitudinal lateral lines of the mesonotum and mesopleurae as well as the having the costal region of the alae not as distinctly striped longitudinally as in feruloides .

Etymology. named after the Tuba Municipality in southern Benguet Province, Luzon, the type locality of this new species. Neuter.

Description. The unique holotype lacks the left front leg and left mesotarsus, but is otherwise in good condition and seems to show no notable discolouration caused by the dehydrating process.

♂ ( Fig. 20 ). Rather small (body length 95.0 mm) and of rather typical form for the genus, but with colouration less complex and more uniform than other Philippine congenerics. Overall colour fairly plain mid to dark green, the abdomen greyish buff with the two terminal terga dark brown; tergum VIII with a light grey lateral marking in basal half. Head greyish ochre, the genae straw-coloured with a bold but faint and washed green postocular streak ( Figs. 20C–D ). Pronotum olive with a brownish wash. Tegmina and costal region of alae cream-coloured with the anterior margin broadly white; all main longitudinal veins marked with dark brown; anal fan hyaline with greyish brown veins. Abdominal terga II–V each with a washed blackish posteromedian marking. Profemora ochre, meso- and metafemora green, all with basal portion slightly bluish and apex washed dark brown. Tibiae ochre with a slight greenish hue and three weakly indicated darker annulae. Antennae greyish brown with ventral surface black in basal one-third.

Head ( Figs. 20C–D ): Oval, somewhat depressed dorsoventrally, only 1.2x longer than wide, broadest at eyes and slightly narrowing towards posterior. Vertex weakly convex with coronal line and lateral furrow slightly impressed and with a notable median impression just behind frons, that laterally extends into a shallow furrow that reaches to the compound eye. Frons shallowly bi-gibbose and with a small C-shaped impression in front. Eyes very large, projecting more than hemispherical and their diameter corresponding to 0.66x length of gena. Antennae slightly projecting over posterior margin of abdominal segment III; scapus somewhat narrowed towards base, the pedicellus round in cross-section and barrel-shaped; following joints slightly and irregularly unequal and essentially first increasing, then decreasing in length.

Thorax: Pronotum shorter and much narrower than head, basically rounded rectangular in outline and 1.8x longer than wide; anterior portion somewhat narrowed and lateral margins gently concave; the anterior margin inflated and bulgy medially and with a small pit some distance off each outer angle; transverse median sulcus distinctly impressed, almost straight and almost reaching to lateral margins of segment ( Figs. 20C–D ). Mesothorax slender, elongate and uniform in diameter with only a slight widening in posterior portion and at anterior margin; almost 8.5x longer than prothorax. Mesonotum with a shallow transverse swelling at anterior margin and a few indicated granules in anterodorsal area. Meso- and metasternum with a fine and rather low medio-longitudinal carina. Tegmina spatulate with basal half gradually narrowing and the central hump fairly well developed and obtusely rounded. Alae reaching about three-quarters the way along abdominal segment III.

Abdomen: Abdominal segments II–VI slightly sub-equal in length but uniform in diameter and about 5.2x longer than wide. Tergum V with an obtusely rounded posteromedian swelling. VII only about 0.75x the length of preceding segments. Sterna II–VII all with a fairly distinct and acute medio-longitudinal carina. Tergum VIII trapezoidal in outline with anterior margin only two-thirds the width of posterior margin; length a little more than half of VII. IX notably longer than VIII, tube-shaped and slightly widened basally; the lateral margins somewhat inward folded. Anal segment only two-thirds the length of IX ( Fig. 20E ), similar in width but somewhat narrowing towards the posterior; obtusely tectate longitudinally with the medio-longitudinal keel most pronounced posteriorly; the posterior margin labiate, slightly inflated, glossy and with a widely triangular emargination. Ventral surfaces of posterior margin supplied with small denticles and facing each other at an angle of ca. 70°. Vomer gently arched towards the left, fairly slender and gradually narrowing towards a short but acute and up-curved terminal hook; the lateral margins notably inflated and the ventral surface with a deep medio-longitudinal furrow ( Fig. 20G ). Phallus strongly enlarged and projecting over posterior margin of poculum. Cerci elongate with apex club-like and noticeably projecting beyond tip of abdomen. The poculum rather small, bowl-shaped with the base moderately bulgy and rounded ( Fig. 20E ) and the posterior margin narrowly rounded; not reaching to posterior of tergum IX ( Fig. 20G ).

Legs: Of average length and shape for the genus; dentations weakly developed and minute. Profemora somewhat longer than head, pro- and mesothorax taken together, mesofemora scarcely longer than pro- and mesothorax combined, metafemora slightly projecting over posterior margin of abdominal segment V and metatibiae projecting considerably beyond tip of abdomen. Teeth of profemora strongly reduced. Mid and hind legs with all carinae fairly regularly denticulate; the medioventral carina supplied with about ten (mesofemora) to about twelve small spines. Tarsi all elongate with basitarsus longer than remaining tarsomeres taken together (just scarcely longer in mesotarsi although); ventral carinae of meso- and metabasitarsi supplied with a few minute denticles.

Measurements [mm]: Body 95.0, pronotum 2.4, mesonotum 24.0, metanotum 3.9, median segment 7.8, tegmina 5.4, alae 24.0, profemora 32.8, mesofemora 26.8, metafemora 31.5, protibiae 34.8, mesotibiae 25.5, metatibiae 33.8, antennae 62.0.

Remarks. Female and egg unknown.

Distribution. Philippines (Luzon, Province Benguet, Tuba Municipality [RBINS – type locality]).

Summary

The genus Sadyattes Stål, 1875 was taxonomically revised at the species level and illustrations of almost all fifteen known species are provided along with identification keys. Six new species have been described from the Philippines and four species are transferred to Sadyattes from other genera. The previously unrecognised ♀ of the type-species S. borrii is re-described and found to have been described as a distinct species. The previously unknown ♂♂ of two species as well as the eggs of two species are described and illustrated for the first time.

Sadyattes was previously only known from a unique ♂ from an unknown locality and thus the taxonomic position and relationships were obscure. The genus was however recognised as a member of the tribe Stephanacridini Günther, 1953 (subfamily Platycraninae ; see Hennemann, 2020) and removed from Pharnaciini ( Clitumninae ) by Hennemann & Conle (2008), where it was placed by Günther (1953). It was until now that additional material has become available which uncovered the identity and type-locality of Sadyattes borrii Stål, 1875 , the type-species of the genus, and represented the key to consequently also allowing a new recognition and delimitation of Sadyattes . As a result, it was found that Eucarcharus Brunner v. Wattenwyl, 1907 is a synonym of Sadyattes (syn. nov.) and that the Javanese paralectotype (the only other type specimen besides the lectotype from the Philippines) of its type species E. feruloides ( Westwood, 1859) , which actually is an endemic of the Philippines, is the opposite sex of Stål’s Sadyattes borrii . Comprehensive new material, especially from the Philippine Islands, has generated as many as six new species from the Philippines that are described herein. This quadruples the number of known species of Sadyattes from throughout the Philippines, since only to species were known previously, namely S. fallax (Brunner v. Wattenwyl, 1907) and S. feruloides ( Westwood, 1859) both of which are here transferred from Eucarcharus (comb. nov.). No new species have been revealed by the present study from the other regions of the distributional range of the genus, but the previously unknown ♂ of the Malayan S. incertus ( Redtenbacher, 1908; comb. nov.) could be accounted for and described for the first time. The three Bornean species of the genus, all of which are only known from one sex, are discussed and it seems likely that at least one of them represents the previously unknown ♀ of a species only known from the ♂, namely S. nigricornis ( Redtenbacher, 1908) and S. decoris Seow-Choen, 2016 ; comb. nov.). In total the number of known species know counts to fifteen, but there are still noteworthy gaps in our knowledge of Sadyattes , because some of species are currently only known from one sex and the eggs of only seven species are known. Thus, two species are only known from the ♂ and three only from the ♀.

The distributional range of Sadyattes is biogeographically interesting in that it comprises great parts of Southeast Asia i. e. islands on the Sunda Shelf (Peninsular Malaysia, Sumatra and Nicobar Islands, Java and Borneo) as well as the Philippine Islands, the latter of which are currently regarded as part of Wallacea (e. g. Vallejo, 2011) as defined by Huxley (1868). The genus has no species in the remainder of Wallacea, e. g. the Maluku Islands or Sulawesi. However, the distribution of Sadyattes fits very well to the definition of Wallace’s Line by Wallace (1876), who placed it southeast of the Philippines. To the current state of knowledge Sadyattes has one species on Java, two on Sumatra (including nearby smaller islands), two in Peninsular Malaysia (one of which also occurs in the Andaman Islands), three species in Borneo and nine species throughout the Philippine Islands. Within the Philippines the distribution of Sadyattes comprises all of the major biogeographical regions with the exceptions of Palawan and the Sulu Islands. However, since there are also representatives in Borneo and the two mentioned Philippine biogeographic regions represent transitions zones between the Philippines and Borneo, it is likely that Sadyattes can also be found there, but there have been no records yet. The small number of known specimens of certain species suggest these to be fairly rare in the corresponding habitats. Only two Philippine species, namely S. maganda sp. nov. from the island of Mindoro and S. mindanaense sp. nov. from Mindanao, appear to be fairly common and abundant in certain localities of their distributional range, which is seen by the large number of specimens that are available for examination.

Very little is known about the natural habitats, life-cycles, behaviours or host plants of Sadyattes -species and only two species, S. leytensis ( Zompro, 1997; comb. nov.) and S. mindanaense sp. nov., have been reared in captivity in Europe for some generations. Seow-Choen (2021: 773) stated to have reared specimens of S. enganensis ( Redtenbacher, 1908) from eggs in captivity and that these accepted guava ( Psidium guayava , Myrtaceae ), Syzygium aqueum ( Myrtaceae ) and mango ( Mangifera indica , Anarcadiaceae) as alternative food plants. These insects are believed to be rather polyphagous than specialized feeders since in captivity in Europe S. mindanaense sp. nov. frequently accepted various plants as alternative nutrition, including guava ( Psidium guayava , Myrtaceae ), eucalyptus ( Eucalyptus spp. , Myrtaceae ), hypericum ( Hypericum patulum , Hypericaceae ), oak ( Quercus spp. , Fagaceae ), beech ( Fagus sylvatica , Fagaceae ), bramble and raspberry ( Rubus spp. , Rosaceae ), wild roses ( Rosa spp. , Rosaceae ) and also strawberry ( Fragaria vesca , Rosaceae ). It is hoped that future collections of species of Sadyattes will also contribute to our knowledge of biological aspects.

The descriptions of as many as six new species of the rarely known genus Sadyattes from the Philippines, which as stated above quadruple the number of species known from the archipelago, are yet again good evidence for the still poor degree of exploration of the phasmid fauna of the Philippine Islands. Some of these newly described species are stunning in the aspect that the ♀♀ are large and the ♂♂ often colourful and therefore eye-catching insects, which makes it even more remarkable that they have not been discovered earlier. But the proportionally high number of newly discovered species lines up very well with other current studies describing a good number of new species from an individual clade (e. g. Hennemann et al., 2016; Cumming et al., 2023; Hennemann, 2023) and the certitude that still a plethora of new species of Phasmatodea from throughout the Philippines await formal description. Many of these species are endemics of individual islands or certain isolated habitats on islands, which may also be the case for some of the newly described species of Sadyattes , for instance S. maganda sp. nov. on the island of Mindoro, S. panayense sp. nov. on the island of Panay and S. tubaense sp. nov. from Luzon. However, still too little is known about these species, two of which are so far only known from a unique holotype specimen. Unfortunately, the impressive biodiversity of Philippine Phasmatodea is badly threatened by a progressive destruction and loss of forest, which are the natural habitat for most phasmids. This becomes obvious by some alarming figures. From 2001 to 2021 the Philippines have lost 158kha of humid primary forest, making up 12% of its total tree cover loss and the total area of humid primary forest in the Philippines has decreased by as much as 3.4% in this period of less than twenty years. Roughly, 92% of this loss occurred in areas where the main reason is deforestation by human (Source: https://globalforestwarch.org, accessed 28.07.2024). Since small and isolated island faunas, of which there are a plethora throughout the Philippine archipelago, are particularly vulnerable, such degrees of deforestations have severe impact on the biodiversity of the Philippines. It is well known that protected forests experience the lowest deforestation rates and thus it must be hoped there will rapidly be considerably more efforts to protect the remaining forest areas and highly tender isolated island faunas within the Philippines to help retain as much as possible of the highly threatened biodiversity of the archipelago, much of which is still so poorly studied. Thus, it is hoped that the descriptions of several large and colourful stick insects such as the species of Sadyattes can support considerations that ensure the survival and protection of endangered areas within the Philippines.

Figures

FIGURE 20. Sadyattes tubaense sp. nov. ♂ holotype [RBINS]: A. Habitus, dorsolateral view; B. Habitus, dorsal view; C. Head and prothorax, lateral view; D. Head and prothorax, dorsal view; E. Terminalia in lateral view; F. Terminalia in dorsal view; G. Terminalia in ventral view. Pha = phallus.