Phobaeticus ingens ( Redtenbacher, 1908 )

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 : 150-153

Phobaeticus ingens ( Redtenbacher, 1908)

( Figs. 101–102, 227–228, 271, 362, 373)

Pharnacia ingens Redtenbacher, 1908: 453 . LT [by present designation], ♀: Meppadi, Malabar, Mr. Atzenwiller; Pharnacia ingens Redtb. Type (MHNG, No. 69) [Not: PLT, ♀: Upper-Tenasserim, Moolai to Moolat, 4000–6000 feet (presumably in NZSI). Recorded by Wood-Mason (1877a: 161) as “ Phibalosoma acanthopus Burmeister, 1839 ”; = Phryganistria grandis Rehn, 1906 ]

Phobaeticus ingens, Brock, 1996: 29 .

Otte & Brock, 2005: 269.

[Not: Phibalosoma acanthopus, Wood-Mason, 1877a: 161 . Misidentification = Phryganistria grandis Rehn, 1906 ]

Further material [5 ♂♂]:

MYANMAR:

2 ♂♂: N-Myanmar, Tenasserim Highland, 18.3.– 19.IV.1996, leg. Lehmann (coll. FH, No’s 0251-1 & 2); 3 ♂♂: Myanmar, Tenasserim, leg. Lehmann V.1995 – 20.IV.1996 (coll. OC).

Diagnosis: This striking species is well characterised by the rather broad and robust body, heart-shaped abdominal tergite VII (Fig. 271), characteristic leg armature, distinct white markings on the complete body and legs and praeopercular organ of ♀♀ which consists of only one central spine-like appendage (two in all other species in the genus, Fig. 362). ♂♂ resemble those of the Bornean Ph. chani Bragg spec. nov. by differ by the smaller size, slightly more robust body, lack of a dark postocular stripe and comparatively broader semi-tergites of the anal segment (Fig. 228).

Etymology: The specific name ingens (lat. = huge, gigantic) refers to the impressive size of the ♀♀ of this beautiful species.

Description: ♀♀ ( Fig. 101): Very large (body length 218.0 mm) and moderately robust species (maximum body width 12.0 mm) with very characteristic leg armature. General colouration of body and legs yellowish to greyish mid brown with great portions of dorsal surfaces of head, meso-, metanotum, median segment and single abdominal tergites white. Ventral surface of body and lateral surfaces of head brown with whitish speckles. Vertex with a bold wedge-shaped white marking. Mesonotum brown at anterior margin with a bold lateral brown patch near posterior margin and irregular brown patterns on lateral margins. Metanotum with brown lateral patterns. Median segment with an elongate brown patch along lateral margins. Tergite II with a bold)(-shaped white marking. Great portions of III and VI white with brown speckles laterally. IV and V brown with a pair of bold white patches near posterior margin; these more elongate and indistinct on V. Posterior portion of VII with two bold, white transverse bands, which are connected at their apices. VIII with a bold white, longitudinal median stripe. IX and anal segment white except for a small irregular brown anterolateral marking. Subgenital plate brown with a white lateral marking sub-basally. Legs more or less distinctly marbled with white. Armature of meso- and metafemora dark drab. Eyes reddish brown. Antennae reddish mid brown.

Head: Oval, 1.6x longer than wide, vertex very gently rounded, with an impression transverse furrow between the eyes. Eyes of moderate size, circular and slightly convex; their length contained 3.5x in that of cheek. Antennae at least projecting over pronotum (broken in the LT). Scapus dorsoventrally flattened, 2.5x longer than wide and gently narrowed towards the base. Pedicellus distinctly shorter than scapus, round in cross-section.

Thorax: Pronotum shorter and slightly narrower than head, about 1.2x longer than wide and with anterior margin narrower than posterior margin. Median transverse depression short, straight and not reaching lateral margins of segment. Entire dorsal surface with an impressed longitudinal median line. Mesothorax decidedly constricted at the anterior and almost 2.5x longer than head and pronotum combined. Mesonotum with a slightly raised longitudinal median line. Metanotum parallel-sided and about 2.6x longer than wide. Mesopleurae set with a longitudinal row of minute but acute granules. Mesosternum with a very faint and irregular longitudinal median line, metasternum smooth.

Abdomen: Median segment a little more than half the length of metanotum, 1.3x longer than wide, parallel-sided. Segments II–VI slightly increasing in length, in average 1.5x longer than wide, parallel-sided. Tergites IV and VI each with a rounded, black posteromedian tubercle, V with a rounded, scale-like lobe. VII strongly dilated into a large, rounded lateral lobe, which projects by more than half the body width, and in dorsal aspect gives the segment a heart-shaped appearance (Fig. 271). Praeopercular organ formed by a single prominent, dorsoventrally flattened, roughly triangular median appendage at posterior margin of sternum VII (Fig. 362). VIII slightly longer but distinctly narrower than VII, 3.5x longer than wide, strongly convex and gently constricted medially. IX about half the length of VIII, indistinctly longer than wide, strongly convex, rectangular. Anal segment longer than IX, flattened towards the apex and with a fine longitudinal median carina, posterior margin with a very shallow concave excavation, outer angles roundly triangular. Supraanal plate very small, rounded and keeled. Cerci small and oval in cross-section. Subgenital plate strongly keeled, boatshaped and tapered towards a blunt apex, which slightly projects over posterior margin of anal segment (Fig. 227).

Legs: All rather long and robust with prominent, characteristic lobes and serrations. Profemora about as long as pro-, and mesonotum combined, mesofemora slightly shorter than mesothorax, metafemora slightly projecting over posterior margin of abdominal segment IV and hind tarsi projecting over apex of abdomen. Meso- and metafemora very gently down-curving. Anterodorsal carina of profemora with 12–13 broad triangular serrations, posteroventral carina with a similar number of long and slender spines. Anterodorsal carina of protibiae distinctly raised, slightly wave-like and protruded into a prominent, triangular median tooth; a further, slightly enlarged tooth near the base and several towards the apex of tibia. Posteroventral carina sparingly serrate. Two outer ventral carinae of mesofemora armed with numerous rather distinct, straight and pointed spines, these considerably enlarged in basal portion of posteroventral carina. Anterodorsal carina smooth except for 3–4 minute teeth. Posterodorsal carina with two slightly enlarged teeth about ¼ off the base and another two slightly enlarged teeth near apex. Metafemora with the two outer ventral carinae minutely and sparingly serrate, dorsal carinae smooth except for a slightly enlarged tooth about ¼ off the base posterodorsal carina. Medioventral carina of meso- and metafemora with 8–12 pointed spines. Posterodorsal carina of mesotibiae protruded into a very prominent, triangular and foliaceous median lobe, a much smaller, triangular lobe about ¾ the way along tibia and a rounded, dentate lobe apically. Medioventral carina very sparingly dentate and with a single enlarged tooth about 1/3 off the base. Posterodorsal carina of metatibiae with a large, triangular median lobe and a rounded, dentate apical lobe. Medioventral carina very sparingly and minutely serrate. Probasitarsus elongate, with the dorsal carina uniformly elevated and unarmed (remaining tarsomeres missing in the LT). Dorsal carina of meso- and metabasitarsus gradually raised towards the apex; as long as following three tarsomeres combined.

♂♂ ( Fig. 102): Medium-sized (body length 117.0– 119.2 mm) and rather slender for the genus with moderately long alae (55.0– 57.5 mm). General colouration of body and legs dark brown, abdomen greyish brown. Mesopleurae with a whitish posterior spot and lateral margins of tergite IX with a bold white longitudinal band. Abdominal sternites irregularly set with indistinct whitish speckles. Cerci grey or yellowish brown. Bases of profemora straw, those of meso- and metafemora and basitarsi dull orange. Armature of legs black. Antennae dark reddish brown. Tegmina and costal region of alae greyish brown (tegmina slightly darker), the latter becoming transparent with dark brown veins towards the interior. Anal region of alae transparent grey with blackish veins. Anterior margin of tegmina and basal half of alae with a longitudinal yellowish white band; this followd by a fine, dark brown interior longitudinal line on tegmina. Eyes dark brown.

Head: Generally as in ♀♀. Between the eyes with a short, curved transverse impression. Eyes very prominent and projecting hemispherically; their length contained less than 2.5x in that of cheek. Antennae projecting over posterior margin of metanotum, with 27–28 segments. Scapus oval in cross-section, slightly narrowed towards the base and about 2.5x longer than wide. Pedicellus ¼ the length of scapus, round in cross- section. Following antennomeres distinctly increasing in length, the seven apical ones decreasing. Terminal antennomere very elongate, as long as four previous combined.

Thorax: Pronotum generally as in ♀♀ but relatively longer. Mesothorax 2.5x longer than head and pronotum combined, slightly broadened posteriorly. Mesonotum set with a very few indistinct granules and minutely rugulose along the lateral margins. Mesosternum with a faint longitudinal median carina; metasternum smooth. Metanotum about ¼ the length of mesonotum. Tegmina elongate, oval, strongly tapered in basal half and with a well decided, conical central hump. Alae reaching to posterior margin of abdominal tergite V.

Abdomen: Median segment about 3.5x longer than metanotum, 4x longer than wide and slightly tapered towards the posterior. Segments II–VI slightly increasing in length, II 4.5x, VI 5.5x longer than wide, all gently constricted medially. Tergite VII shorter than VI, about 5x longer than wide and slightly expanded posteriorly. V–VII each with a small posteromedian tubercle. VIII 2/3 the length of VII, 2.3x longer than wide, broadening towards posterior margin and strongly convex; broadest segment. IX slightly shorter than VIII, strongly convex and constricted medially; anterior margin broader than posterior margin. Anal segment as long as IX. Semi-tergites very broad, indistinctly longer than high with the apex strongly angled and roundly truncate, lower apical angle acute (Fig. 228). Interior surface densely set with small black teeth. Cerci obtuse, rather elongate, oval in cross-section, gently in-curving and slightly projecting over apex of anal segment. Poculum strongly convex, cup-like and reaching about 2/3 the way along tergite IX; posterior portion with a slight longitudinal median carina.

Legs: All moderately long and slender, profemora about as long as head, pro-, and mesonotum combined, mesofemora slightly longer than pro-, and mesonotum combined, metafemora reaching about half way along abdominal segment V and hind tarsi slightly projecting over tip of abdomen. Armature similar as in ♀♀ but considerably less developed. Anterodorsal carina of profemora with 7–14 very prominent black, triangular serrations; posteroventral carina with 8–15 smaller black teeth. Anterodorsal carina of protibiae smooth, except for 1–3 flat, broad lobes in great but equal distance to another and a few minor basal serrations; the median lobe largest and occasionally the proximal and apical ones very indistinct. Posteroventral carina sparingly and minutely serrate. All carinae of meso- and metafemora serrate, more sparsely but distinct on dorsal carinae. Medioventral carina set with 11–14 small spines. Two outer ventral carinae of mesofemora very slightly dilated basally with teeth more prominent in this portion. All carinae of meso- and metatibiae minutely serrate. Posterodorsal carina with a prominent, triangular median lobe and raised into a prominently rounded and dentate lobe at the apex. Probasitarsus with a slightly raised dorsal carina and almost 1.5x longer than remaining tarsomeres combined. Meso- and metabasitarsus slightly longer than combined length of remaining tarsomeres, dorsal carina gently rounded and occasionally with one or two minute teeth.

Comments: Redtenbacher (1908: 453) described Pharnacia ingens based on a ♀ from the Malabar Coast, southwestern India in MHNG and a ♀ from Upper Tenasserim, Myanmar. The latter ♀ is a specimen that had erroneously been recorded as “ Phibalosoma acanthopus Burmeister, 1839 ” by Wood-Mason (1877a: 161). Redtenbacher recognized Wood-Mason’s misidentification and decided the ♀ from Myanmar to be conspecific to the ♀ in MHNG, which is however certainly not the case. The whereabouts of Wood-Mason’s specimen have so far remained unknown although it is persumed to be traced in NZSI. Inquiries have however not received any reply. Therefore, the ♀ from India in MHNG is here selected as the LT of Ph. ingens since it is the only specimen which Redtenbacher had examined himself. Wood-Mason’s specimen from Myanmar, the PLT, most certainly belongs in Phryganistria Stål, 1875 (→ Phryganistria grandis Rehn, 1906 ). Redtenbacher (1908: 453) cited body lengths of 208.0 and 260.0 mm, the latter referring to the PLT.

The presence of a praeopercular organ in ♀♀ confirms the current placement in Phobaeticus Brunner v. Wattenwyl, 1907. The organ itself however is of a structure rather different from other Phobaeticus -species, consisting of only one triangular, lobe-like appendage at posterior margin of abdominal sternum VII. This feature readily distinguishes ♀♀ from those of all other species, all of which have two appendages.

Examination of five ♂♂ from Myanmar in the authors collections and comparison with the LT of Ph. ingens has shown these widely correspond in leg armature and shape of the head and thorax, thus might represent the opposite sex. However, without seeing large series of both sexes from the same locality, these ♂♂ are here assigned with doubt only. The short median segment of ♀♀ would suppose the corresponding ♂♂ to be apterous rather than having fully developed alae. Furthermore , there is a distance of more than 1500 kilometres between the type-locality (Malabar Coast, SE. India) and the Highland of Tenasserim in northern Myanmar. Also, as can be seen in other species of the genus size and armature of the legs are subject to strong intraspecific variability and concerns to both sexes, which is an additional factor that renders the correct assignment of sexes more difficult. Eggs unknown .

Distribution (Fig. 373): Southwest India (Malabar Coast: Meppadi) and Northern Myanmar (Highland of Tenasserim).

Number of specimens examined: 6