Sadyattes decoris ( Redtenbacher, 1908 ), 2025

Sadyattes decoris ( Redtenbacher, 1908) View in CoL comb. nov.

( Figs. 21K–L View FIGURE 21 , 23A View FIGURE 23 )

Phobaeticus decoris Seow-Choen, 2016: 151 View in CoL , figs. HT, ♀: Phobaeticus decoris, Serapi, I. Abercrombie View in CoL , HOLOTYPE 12.8.96 [LKCNH]; PT, ♀: Phobaeticus decoris, Bako NP View in CoL , Paratype, 12.6.99, FSC [ SMSM] .

Seow-Choen, 2019: 266.

Brock & Büscher, 2022: 554.

Differentiation. The ♀ ( Fig. 23A View FIGURE 23 ) of this Bornean species (the only sex known) most closely resemble the Philippine S. panayense sp. nov. with which they share the overall appearance and shape, as well as the size and elongated, lanceolate subgenital plate. This species however is geographically well separated from any Philippine congenerics and moreover differs from panayense by the more elongate head, much smaller serrations of the limbs and notably longer subgenital plate, which extends beyond the tip of the abdomen by the combined length of abdominal terga VIII–X. The only similar Bornean species is S. mjoebergi (Günther, 1935) , which however is much larger (body length of the holotype including subgenital plate 249.0 mm), has the medioventral carina of the meso- and metafemora unarmed and the subgenital plate even longer. At first glance ♀♀ of decoris also strongly resemble those of S. incertus (Brunner v. Wattenwyl, 1907) from Peninsular Malaysia, Bangka Island east of Sumatra and the Andaman Islands. They can however be separated by the smaller size (body length including subgenital plate> 189.0 mm in incertus ) and somewhat stockier overall shape and stockier limbs, more ovoid head, smaller and rather serrate than spinose dentations of the extremities, shorter subgenital plate, which extends beyond the tip of the abdomen by no more than the length of the three terminal abdominal terga taken together, and less pronounced praeopercular organ.

Egg ( Figs. 21K–L View FIGURE 21 ). The following description of the eggs is presented because Seow-Choen (2016: 269, Fig. 609) only presented a picture and based on colour photographs kindly provided by Francis Seow-Choen ( Singapore). Unfortunately, none of the pictures is scaled, no measurements were taken and no samples were saved for further study since these eggs laid by the paratype were used for a trying to breed the species (personal communication with F. Seow-Choen) .

Size unknown. Shape very elongate for the genus, chorion 1.8x longer than high, flattened laterally and distinctly oval in cross-section; polar-area with a deep crater-like central indention and the dorsal and ventral surfaces each with a central impression, which is more pronounced on dorsal surface; posterior portions of dorsal and ventral surfaces bulgy, the posterodorsal swelling with an indention below. Surface slightly shiny, minutely coriaceous and unevenly pitted; an arched transverse row of 5–7 deep and enlarged pits ventrally on lateral surfaces and a transverse rim of notably enlarged pits also below anterior margin; the latter raised and densely covered by small, uneven, longitudinally directed rugulae. Micropylar plate positioned roughly in centre of medio indention of dorsal surface, small, roughly one-third as long as capsule with the broadened upper portion drop-shaped and the posterior portion strongly narrowed; outer margin somewhat bulgy and the surface indented and concave. Micropylar cup just above posterior narrowing of plate and distinctly bowl-shaped. Operculum sub-circular, slightly ascending towards the centre and with fine radially directed ridges. Capitulum a large, basally cylindrical protrusion. That has the apex constricted with the upper margin irregularly crenate, down-folded and roughly star-shaped. Colour reddish ochre to dark russet and the micropylar cup straw-coloured. Operculum and capitulum dark orange, the latter with the folded upper margin greyish brown.

Remarks. This species was described from the ♀ and egg. Characteristic morphological traits such as the low but minutely dentate medioventral carina of the profemora, which is roughly central on the ventral surface of the profemur, indistinct pit-shaped praeopercular organ and bowl-like basal swelling of the subgenital plate as well as the distinctive egg morphology clearly place decoris in the genus Sadyattes , hence it is here removed from its original genus Phobaeticus Brunner v. Wattenwyl, 1907 (comb. nov.). Moreover, decoris is not unlikely to be the opposite sex of S. nigricornis (Redtenbacher, 1935) if the distribution in Borneo and the size relations of ♂♂ and ♀♀ within Sadyattes into account. The holotype of nigricornis was said to have a body length of 104.0 mm ( Redtenbacher, 1908: 451), which is fairly small for the genus, thus the ♀ of this species should be an insect that measures about 15–16 cm in length. However, specimens of both sexes from the same locality or from captive breeding are needed for examination to prove or disprove the assumption that nigricornis and decoris are conspecific. Therefore, the ♂ is to be regarded as unknown. Since Seow-Choen (2016) only presented a picture of the eggs of decoris but no description, a formal description is here presented. Body length of ♀♀ (including subgenital plate) 158.0–165.0 mm.

Distribution. NW-Borneo, Sarawak (Mount Serapi [LKCNH]; Bako National Park [SMSM]).