Phobaeticus sobrinus Brunner

Hennemann, Frank H. & Conle, Oskar V., 2008, Revision of Oriental Phasmatodea: The tribe Pharnaciini Günther, 1953, including the description of the world's longest insect, and a survey of the family Phasmatidae Gray, 1835 with keys to the subfamilies and tribes (Phasmatodea: " Anareolatae ": Phasmatidae), Zootaxa 1906, pp. 1-316 : 192-195

Phobaeticus sobrinus Brunner v. Wattenwyl, 1907

( Figs. 121, 264, 336, 394)

Phobaeticus sobrinus Brunner v. Wattenwyl, 1907: 184, pl. 7: 1a–b (♂). LT, ♂: Sumatra, Si-Rambé, XII. 1890 - III.1891, E. Modigliani; Type; Phobaeticus sobrinus Br. (MCSN) . [Not: PLT, ♀: Nias Island, 1897–1898, leg. U. Raap (MCSN). This is clearly a distinct species and not a member of Phobaeticus ; see comments below] Brock, 1996: 30. [Designation of LT] Otte & Brock, 2005: 270.

Phobaeticus beccarianus Brunner v. Wattenwyl, 1907: 185. HT, ♀ (penultimate instar nymph): Sumatra, Mt. Singalang, Luglio, leg. Beccari VII. 1878; Type, Beccarianus Brunner v. W.; Phobaeticus beccarianus Br. (MCSN) syn. nov. Brock, 1996: 28. Otte & Brock, 2005: 268.

Pharnacia beccarianus, Günther, 1935b: 139 .

Diagnosis: Related to Ph. serratipes ( Gray, 1835) but differing by: the smaller size; shorter median segment and pale orange bases of the profemora of both sexes; less prominent posteromedian excavation of the anal segment and prominent dorsal and ventral lobes of the mesofemora and meso- and metatibiae of ♀♀, as well as the lack of tegmina and alae and dorsally rounded anterodorsal crest of the anal segment of ♂♂. ♀♀ are only known from a unique penultimate instar nymph but appear to differ from the also related and Sumatran Ph. mucrospinosus spec. nov. by: the smaller size (estimated ± 200.0 mm when adult); slightly more robust body and different armature of the mid and hind legs.

Etymology: “ Sobrinus ” (lat. = inconspicuous).

Description: ♀♀ (penultimate instar nymph): Moderately long (body length 163.0 mm; estimated to be ± 200.0 mm when adult) and slender species (maximum body width ± 4.0 mm) with characteristic leg armature. General colouration ochracheous mid brown, with slightly darker areas on abdomen and very faint darker transverse bands on the mid and hind legs. Head with a slightly paler brown, coronal-line and a faint, broad postocular line. Bases of all femora pale orange, those of the profemora in particular. Eyes dark ochracheous. Antennae brown and becoming paler towards the base.

Head: Oval, almost 1.5x longer than wide, oval in cross section and slightly narrowing towards the posterior. Eyes small, circular and slightly projecting from head capsule; length contained less than 3x in that of cheeks. Antennae at least reaching half way along mesonotum (broken in the HT). Scapus dorsoventrally compressed, about 2.5x longer than wide and slightly constricted towards the base. Pedicellus distinctly shorter than scapus, round in cross-section, sub-spherical.

Thorax: Pronotum slightly narrower than head but of almost equal length, 1.5x longer than wide and narrowed in anterior portion. Transverse median depression very gently curved and almost reaching lateral margins of segment. Mesothorax almost 4x longer than head and pronotum combined and 2.5x longer than metanotum. Mesonotum parallel-sided and with a very faint longitudinal median line. Metanotum about 4.5x longer than wide, parallel-sided. Pleurae and sterna simple.

Abdomen: Median segment slightly more than 2/3 the length of metanotum, gently constricted medially. Segments II–VI cylindrical and increasing in length, II 2x, III and IV 3.5x, V 4x and VI slightly more than 4x longer than wide. II gently narrowing towards the posterior, III–VII parallel-sided. VII slightly narrower than previous and about ¾ the length of VI. Praeopercular organ, formed by two small, laterally compressed teeth at posterior margin of sternum VII. Tergite VIII shorter than VII, longer than IX and X combined , strongly convex and parallel-sided. IX less than half the length of VIII, indistinctly longer than wide and trapezoidal, gradually widening towards posterior margin. Anal segment ¾ the length of IX, with a fine median carina and a small triangular notch posteromedially. Supraanal plate very small, rounded and keeled. Cerci very small, cylindrical and tapered towards a pointed tip. Subgenital plate keeled and scoop-shaped (not fully developed in the HT).

Legs: All very long and slender, mid and hind legs gently down-curving. Profemora almost as long as head, pro- and mesothorax combined, mesofemora about as long as mesothorax, metafemora slightly projecting over posterior margin of abdominal segment IV and metatarsi exceeding apex of abdomen. Anterodorsal carina of profemora densely and prominently serrate, posteroventral carina densely dentate. Posterodorsal carina very faint and armed with 3–4 minute, triangular teeth.. All carinae of protibiae unarmed except for a few minute teeth on posteroventral carina and a single enlarged, triangular tooth just before middle of tibia on posterodorsal carina. Anterodorsal carina of mesofemora with three prominent, triangular lobes in great but roughly equal distance (Fig. 336). Posteroventral carina slightly dilated sub-basally and in this portion with 2– 3 prominent teeth. All other carinae dentate. Metafemora with all carinae dentate, although more minute and sparsely on dorsal carinae. Medioventral carina of meso- and metafemora indistinct and armed with a few minute spines. Posterodorsal and medioventral carinae of meso- and metatibiae each with a large, roundly triangular lobe about 1/3 off the base; the dorsal lobe considerably larger. Probasitarsus as long as remaining segments combined except claw, unarmed. Meso- and metabasitarsi as long as following three segments combined, dorsal carina slightly rounded and all carinae minutely dentate.

♂♂ ( Fig. 121): The ♂ LT of Ph. sobrinus is in poor condition with most extremities glued. It lacks the right hind leg, right mesotibia and complete right protarsus as well as the four terminal segments of the left protarsus, complete left metatarsus and great parts of the antennae.

Rather small (body length 125.0 mm) and slender for the genus, apterous. General colouration of body and legs yellowish brown with slightly darker areas on abdomen. Head with a pale brown coronal line and a washed, roughly triangular pale marking between the eyes. Meso- and metasternum as well as bases of profemora pale orange-brown. Lateral margins of meso and metathorax with a faint blackish longitudinal line. Armature of legs very dark reddish brown. Eyes reddish brown with darker brown mottling. Antennae dark brown dorsally and black ventrally, two basal antennomeres pale brown.

Head: Oval, almost 1.5x longer than wide, broadest at eyes and strongly narrowing towards posterior margin. Between the bases of the antennae with an oval, slightly raised and smooth area. Eyes very prominent and projecting hemispherically from head capsule; their length contained only about 1.7x in that of cheeks. Antennae longer than head and pronotum combined (broken in the LT). Scapus dorsoventrally compressed, constricted towards the base and about 3x longer than wide. Pedicellus distinctly shorter than scapus, subspherical.

Thorax: Pronotum generally as in ♀♀, almost equal in length to head but distinctly narrower, the anterior portion narrowed. Median transverse depression distinct, gently curved and reaching to lateral margin of segment. Mesothorax almost 4x longer than head and pronotum combined, mesonotum parallel-sided except for being very slightly broadened at posterior margin. Metanotum less than half the length of mesonotum 6x longer than wide, parallel-sided. Meso- and metasternum with a faint longitudinal median carina. Tegmina represented by a pair of very small, oval lobes (c. 1.0 mm).

Abdomen: Median segment 2/3 the length of metanotum, almost 5x longer than wide and slightly broadening towards the posterior. Segment II 4.5x longer than wide slightly shorter than median segment. III–VI in average 5.5x longer than wide and slightly constricted medially. VII shorter than VI and slightly widening towards posterior margin. Tergites V and VI with a small tubercle posteromedially. VIII swollen and gradually broadening towards posterior margin and less than 2.5x longer than wide. IX slightly shorter than VIII, anterior margin broader than posterior margin, strongly constricted medially and convex with a fine median carina. Anal segment as long as VII, strongly keeled, laterally compressed and tectiform. Semi-tergites long, straight and finger-like with a rounded apex (Fig. 264). The interior surface apically set with minute black spines. Cerci moderately long, slender, round in cross-section and incurving in apical portion. Poculum strongly convex, cup-like, not reaching about half way along tergite IX and with a prominent but blunt central spine.

Legs: All very long and sender, profemora considerably longer than pro-, meso- and metathorax combined, mesofemora a little longer than pro- and mesothorax combined, metafemora reaching to abdominal segment VI and metatibiae projecting exceeding apex of abdomen. Anterodorsal carina of profemora with 19– 22 prominent, sharply triangular serrations. Posteroventral carina with a similar number of small but pointed teeth. Protibiae unarmed except for a few minute serrations on posteroventral carina. Two outer ventral carinae of meso- and metafemora sparsely armed with small, pointed teeth, dorsal carinae with only very few minute teeth. Medioventral carina of meso and metafemora indistinct and armed with a few very minute spines. Meso- and metatibiae with all carinae minutely dentate, more sparsely on dorsal carinae. Probasitarsus very long and slender, dorsal carina very slightly raised, all carinae unarmed (remaining tarsomeres missing in LT). Mesobasitarsus as long as remaining segments combined and with all carinae minutely dentate.

Comments: Brunner v. Wattenwyl (1907: 184) described Phobaeticus sobrinus based on adult ♂ and ♀ both in MCSN. Brock (1996: 28) designated the ♂ from Sumatra (Si-Rambé) as LT and selected Ph. sobrinus Brunner v. Wattenwyl as the type species of Phobaeticus Brunner v. Wattenwyl, 1907. Detailed examination of the ♀ PLT from Nias Island and comparison with the ♂ LT has clearly shown these to represent two distinct specie, which do not even belong in the same genus. The shape of the anal segment and genitalia, lack of an elevated and displaced, ledge-like medioventral carina of the profemora as well as the oval body cross-section place the ♀ PLT in close relation to the genus Nesiophasma Günther, 1934 (tribe Stephanacridini ). Clarification if its generic position including a description is in progress by the authors.

The HT of Ph. beccarianus Brunner v. Wattenwyl in MCSN is a penultimate instar ♀ nymph, which may have reached an estimated body length of ± 200.0 mm when adult. Examination and careful comparison with the ♂ LT of Ph. sobrinus has shown Ph. beccarianus merely to represent the corresponding ♀ (syn. nov.) .

Only known from the type specimens. Eggs unknown.

Distribution (Fig. 394): W-Sumatra (Si-Rambé & Mount Singalang).

Number of specimens examined: 2

The following species, Phobaeticus incertus Brunner v. Wattenwyl, 1907, is provisionally retained in the genus Phobaeticus Brunner v. Wattenwyl but with doubt.

It differs considerably from all other members of Phobaeticus Brunner v. Wattenwyl, 1907 by lacking a praeopercular organ in ♀♀. It furthermore differs from entire Pharnaciini by having the medioventral carina of the profemora serrate and about midways on the ventral surface of the femur. The egg as well differs considerably from all other known eggs of Phobaeticus and is rather unlike those of other Pharnaciini , having a very small, rhomboidal micropylar plate and the capsule irregularly impressed and covered with wart-like structures. Unfortunately, the internal micropylar plate is as yet unknown but the rhomboidal shape of the plate is usually associated with closed plates (Figs. 167–168). The supposedly closed internal micropylar plate and structure of the medioventral carina of the profemora would place Ph. incertus in the tribe Stephanacridini and indeed the general appearance and shape of the genitalia, such as the laterally excavated anal segment (Fig. 252), indicate relation to the genera Eucarcharus Brunner v. Wattenwyl, 1907 and Nesiophasma Günther, 1934 (→ 4.7.2). The egg shows similarity to those of e.g. Nesiophasma plateni ( Dohrn, 1910) in several aspects ( Fig. 60). However, without having at hand ♂♂ and ♀♀ from the same locality and knowledge of the internal micropylar plate of the eggs it is for now difficult to decide about the taxonomic position of Ph. incertus with confirmation. A clarification is in progress by the authors.

Despite the unconfirmed taxonomic position a complete treatment of this species is presented below.