Sadyattes enganensis ( Redtenbacher, 1908 )

Sadyattes enganensis ( Redtenbacher, 1908) View in CoL

( Figs. 21O–P View FIGURE 21 )

Pharnacia enganensis Redtenbacher, 1908: 451 View in CoL . LT, ♂: Engano, Bua Bua V.-VI., Modigliani 1891; 4; Lectotypus [MSNG]; PLT, ♂: Engano, Bua Bua V.-VI., Modigliani 1891; Paralectotypus [MSNG]. Phobaeticus enganensis, Brock, 1996: 28 View in CoL . [Lectotype designation] Sadyattes enganensis, Hennemann & Conle, 2008: 132 View in CoL . Seow-Choen, 2018: 452, Figs. [Illustrations of LT and PLT] Seow-Choen, 2020: 396. Seow-Choen, 2021: 772, Figs. 729-737. [Description of ♀] Brock & Büscher, 2022: 559.

Phobaeticus sobrinus Brunner View in CoL v. Wattenwyl, 1907: 184 (in part – only PLT). PLT, ♀ (penultimate instar): Is. Nias, 1897-1898, U. Raap; 22; Phobaeticus sobrinus Br. View in CoL [MSNG].

Further material:

1 ♂: Kleiwegde Zwaas, Nias 1911; Pharnacia acanthopus Burm. K. Günther det. [ RMNH] ; 1 ♂: Penang Hills , 1800-2500 ft. S.S. Flower, 99-248 [ NHMUK] ; 1 ♀: West Malaysia, Perak, Tapah Hills ca. 800 m, local collector V.2013 [ FH, No. 1458-1] ; 1 ♀: W. Indie [ NHMM] .

Differentiation. Both sexes of this distinctive species are morphologically closest to the type-species S. borrii Stål, 1875 from Java and Sumatra with which they share the distinctive pale cream-coloured protarsus of both sexes. Females of these two species also share the distinct posterolateral lobes of abdominal terga VIII-X, shape of the anal segment, which has the lateral margins deeply and almost semi-circularly excavated and the posterior margin broadly bi-lobed, as well as the rounded dorsal lobe of the probasitarsus. However, this species is more robust in overall shape with comparatively stockier legs, has abdominal segments III–VI distinctly swollen, the subgenital plate more acutely pointed apically and the dorsal lobe of the probasitarsus higher than in borrii . Males of enganensis are readily separable from those of borrii by the slightly stockier form, which includes notably shorter abdominal segments II–VI (4x vs. 6.5x longer than wide in borrii ), more globose head which has the vertex notably more convex, more club-shaped apex of the abdomen with abdominal segments VIII and IX notably stronger inflated, shorter and gently arched vomer, having a dark brown medio-longitudinal streak on the tegmina, having all the dentations of the limbs more obtuse and not as distinctly black as in borrii and lacking the distinctively orange outer ventral carinae of the meso- and metafemora seen in borrii . From the known eggs of the genus, those of enganensis ( Figs. 21O–P View FIGURE 21 ) most closely resemble the eggs of incertus but differ by the punctured chorion surface, lack of the antero-ventral and dorsal and posteroventral impressions of the chorion, flattened polar-area, presence of two prominent sub-parallel longitudinal dorsal ridges and the much longer spearhead-shaped micropylar plate.

Egg ( Figs. 21O–P View FIGURE 21 ). The following description is based on scaled colour photos taken of eggs from Peninsular Malaysia by Francis Seow-Choen ( Singapore) the late Michael K. P.Yeh (Ipoh, Malaysia) and is meant to accomplish the treatment of this species. Unfortunately, no samples were secured (personal communication with F. Seow-Choen).

Fairly large, chorion just slightly longer than high, somewhat flattened laterally and angularly oval in cross-section; polar-area flattened to slightyl concave and rectangular with rounded lateral surfaces in outline and surrounded by a ridge; dorsal and ventral surface each with a sub-parallel pair of distinct, longtitudinal ridges (those of the dorsal surface more prominent than those of the ventral surface. Capsule surface sparsely but distinctly punctured and with a weakly raised network of unevenly granular bulges; polar area somewhat raised and granulose in centre and with a circle of about ten pits. Micropylar plate placed between the two longitudinal ridges, somewhat displaced towards the posterior, rather large and almost two-thirds as long as chorion; spearhead-shaped with the posterior portion strongly narrowed and gradually tapering towards a narrow tip; outer amrgin somewhat raised the surface even, slightly concave and in centre with an oval, granular swelling. Micropylar cup positioned just above posterior narrowing of plate, flat and slightly bowl-shaped. Operculum slightly oval and flat with the outer margin somewhat raised. Capitulum large, conical and star-shaped in dorsal aspect with a distinct ridge running towards the centre from each of the six tips. Colour ranging from orangey ochre over russet to dark brown; the granules yellowish. Capitulum dark straw-coloured.

Measurements [mm]: Length incl. operculum 4.8, length 4.2, width 3.5, height 3.8, length of micropylar plate 2.8.

Remarks. This species was originally described from two ♂♂ from the island of Enggano, southwest off Sumatra in the collection of MSNG and Redtenbacher (1908: 451) stated “ This species differs from all other known species [of Pharnacia ] by the almost club-shaped apex of the abdomen ”. Seow-Choen (2018: 452) presented a translation of Redtenbacher’s original description and illustrations of the lectotype ♂ in the collection of MSNG. Seow-Choen (2021) described the previously unknown ♀ and provided detailed figures of both sexes and the eggs based on specimens from Peninsular Malaysia, as well as figures of the ♂ paralectotype in MSNG and ♂ from Penang Hills, Peninsular Malaysia in the collection of NHMUK. Since this author missed out to give a description of the eggs, this is given above along with measurements based on scaled photos provided to the author by Francis Seow-Choen ( Singapore) the late Michael K. P. Yeh (Ipoh, Malaysia). Seow-Choen (2021: 772) mentioned Psidium guajava ( Myrtaceae ), Mangifera indica (Anarcadiaceae) and Syzygium aqueum ( Myrtaceae ) as foodplants.

Hennemann & Conle (2008: 194) have pointed out that the penultimate instar ♀ paralectotype of Phobaeticus sobrinus Brunner v. Wattenwyl, 1907 from the island of Nias was specifically distinct from the ♂ lectotype from Si- Rambe, Sumatra (both in MSNG) and is not even congeneric. This was confirmed by Seow-Choen (2018: 426), who provided a description of the ♀ as well as illustrations of both sexes and the intraspecific variability of Phobaeticus sobrinus , which actually is a fairly common species on mainland Sumatra. The now more comprehensive knowledge of S. enganensis and examination of a ♂ of enganensis from the Island of Nias in the collection of RMNH show the paralectotype of sobrinus to be a specimen of enganensis . Body length of the specimen is 125.0 mm.

Females show considerable variability in colouration, which was illustrated by Seow-Choen (2021, figs. 727– 732). The great majority of specimens appear to be whitish or cream coloured and variably flecked with different tones pf grey, brown and black. Occasionally the limbs possess a slight greenish to olive wash. So far, only one almost plain green specimen has become known, which only has some dark posterior spots on abdominal terga II-V. A ♀ from the Tapah Hills, Perak, Peninsular Malaysia an examined from photos taken by the late Michael K. P. Yeh (Ipoh, Malaysia) is basically pale olive with light greyish mottling. Body lengths ♂♂ 117.0– 129.5 mm, ♀♀ (incl. subgenital plate) 158.0–183.0 mm .

Distribution. Indonesia: Enggano Island (Bua Bua [MSNG – type locality]); Nias Island [MSNG, RMNH]. Peninsular Malaysia: Perak (Pulau Penang, Penang Hills 1800–2500 ft. [NHMUK]; Tapah Hills [FH, FSC]).