Pharnacia tirachus ( Westwood, 1859 ), 2008

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 : 122-126

Pharnacia tirachus ( Westwood, 1859) stat. rev.

( Figs. 96–97, 155–156, 205–207, 294–295, 316–317, 322, 337, 378)

Phibalosoma tirachus Westwood, 1859: 75 , pl. 37: 3. HT, ♂: Cantor leg., Malacca (OXUM).

Pharnacia tirachus, Brock, 1995: 95 .

Phobaeticus tirachus, Brock, 1996: 30 .

Seow-Choen, 2000: 38, pl. 97 (♂).

Otte & Brock, 2005: 270.

Tirachoidea tirachus, Brunner v. Wattenwyl, 1893: 83.

Kirby, 1904a: 359.

Clitumnus irregularis Brunner v. Wattenwyl, 1907: 195. HT / ST ♀ (♀) nymph(s): Java, Buitenzorg, Pedastshenko (ZMAS – not traced). syn. nov.

Baculum irregularis, Brock, 1998a: 37 .

Otte & Brock, 2005: 303.

Ramulus irregularis, Brock, 2006: 55 . [Syntypes retained in NHMW]

Further material [1 ♀, 2 ♀♀ (nymphs), 7 ♂♂, eggs]:

PENINSULAR MALAYSIA:

1 ♀, 3 eggs: Malacca, Perak, A. Grubauer leg.; B. Jachau vend. 15.12.1901 ( ZMUH) ; 2 ♂♂: Penang Hills , 1800– 2500ft., S.S. Flower; 99-248 ( BMNH) .

JAVA:

1 ♀ (nymph): Buitenzorg , Java occident., Pedaschenko 1901; Coll. Br. v. W.; 26.235 ( NHMW, No. 335) ; 1 ♀ (nymph): Buitenzorg , Java occident., Pedaschenko 1901; Coll. Br. v. W. ( NHMW, No. 335) ; 2 ♀♀ (nymphs): W. Java, Gedeh , Tjibodas, Dr. Siebert ( MNHU) ; 3 ♂♂: W. Java, Gedeh , Tjibodas, Dr. Siebert; Pharnacia hypharpax Westwood, 1859 , K. Günther det. ( MNHU) ; 1 ♂: Kendeng-Geb., O. - Java , 3-4000´, A. Heyne, Berlin-Wilm. I; Pharnacia hypharpax Westwood, 1859 , K. Günther det. ( MNHU) ; 1 ♂: Java ( ZSMC) .

Diagnosis: This species is well characterized by the very elongate, posteriorly narrowed head and flat vertex (Figs. 294–295) and very slender body of both sexes. It is closely related to the Philippine Ph. kalag Zompro, 2005 and Ph. heros Redtenbacher, 1908 from Java.

From the first ♀♀ are easily distinguished by: the presence of at least 3 conspicuously enlarged lobes on the anterodorsal carina of the protibiae (Figs. 316–317); distinct sub-basal lobe of the antero and posteroventral carinae of the mesofemora; more prominent and less acute serrations or lobes of the anterodorsal carina of the profemora and differently shaped lateral lobes of abdominal tergite VII. The eggs differ considerably in being more globose and having the micropylar plate considerably larger with the posterolateral extensions much more elongate (Figs. 155–156). ♂♂ differ by the relatively shorter apically more acutely triangular semi-tergites of the anal segment (Fig. 207), different leg armature and more distinct apical lobe of the meso- and metatibiae.

Apart from the characteristic features mentioned also differing from Ph. heros by: the presence of enlarged, ± foliaceous lobes on the anterodorsal carina of the protibiae; very prominently dentate or lobed anterodorsal carina of the profemora and broader lateral lobes of abdominal tergite VII of ♀♀ as well as the less constricted but acutely distinctly triangular apex of the semi-tergites of the anal segment of ♂♂ (Fig. 207).

Etymology: The specific name is possibly based on “ Tirachus ” a shortened form of Tiberius Sempronius Gracchus (162–133 a. Chr.), a great Roman politician.

Description: ♀♀ ( Fig. 96): Long (body length 195.0 mm) and slender for the genus (maximum body width 8.0 mm). General colouration of body and legs drab to ochracheous brown with various darker markings. Head, pronotum and tergites IV–V darker than rest of body. Head with a bold oval whitish marking between the eyes. Mesonotum slightly darker brown at anterior margin. Median segment dark greenish brown along lateral margins. Abdominal tergite II with an indistinct elongate longitudinal dark greenish brown marking on both sides of the median line. Tergites IV–X irregularly spotted with pale and mid brown, lateral margins of VI–VII slightly whitish. Apical 1/3 of profemora marbled with white, remaining portion more or less uniformly coloured. Apex of protibiae pale greyish brown. Meso- and metafemora marbled with greyish white, tibiae darker brown with slightly paler apices. Bases of basitarsi greyish white. Eyes dark orangebrown. Antennae dark brown in basal portion and becoming reddish brown towards the apex.

Head (Fig. 294): Elongate, almost 2.5x longer than wide, and narrowing towards posterior margin which is slightly angled and indistinctly projecting over anterior margin of pronotum; vertex flat. Between the eyes with an indistinct curved depression. Eyes small, circular and slightly projecting from head capsule; their length contained more than 4x in that of cheek. Antennae consisting of 26–27 segments and reaching about 1/ 3 the way along mesonotum. Scapus dorsoventrally flattened, parallel-sided and about 2.5x longer than wide. Pedicellus half the length of scapus, cylindrical.

Thorax: Pronotum narrower and only half as long as head, about 1.5x longer than wide and gently narrowed towards the anterior. Median transverse depression indistinct, slightly curved and not reaching lateral margins of segment. Median line distinct. Mesothorax very elongate, about 2.2x longer than head and pronotum combined and not considerably constricted anteriorly. Mesonotum with an indistinct pale longitudinal median line and very sparsely set with a few minute granules. Metanotum slightly less than half the length of mesonotum, 3x longer than wide, parallel-sided and with a very indistinct longitudinal median line. Meso- and metasternum smooth.

Abdomen: Median segment slightly shorter than metanotum, 2.5x longer than wide, parallel-sided and posterior margin with a minute median tubercle. Segments II–IV increasing in length, V–VII decreasing, IV longest and almost 3x longer than wide. Tergites II–VII each with a small, scale-like posteromedian tubercle. VII ¾ the length of IV and posterolaterally dilated into a rounded lobe, which projects by about 1/3 of the body width. Sternum VII with two minute granules close to posterior margin. Tergit VIII narrower and shorter than previous, strongly convex and slightly constricted medially. IX parallel-sided, indistinctly longer than wide, roughly rectangular. Anal segment considerably longer than IX and with a fine median carina, posterior margin with a rather deep, roundly truncate median excavation; outer angles slender and truncate (Fig. 206). Supraanal plate small, broadly rounded and with a distinct median keel. Cerci small, oval in cross-section and slightly up-curving. Gonapophyses moderately elongate, up-curving and staying beyond posterior margin of anal segment. Subgenital plate strongly keeled, boat-shaped and just not reaching apex of anal segment (Fig. 205).

Legs: All long and slender, mid and hind legs very gently down-curving. Profemora almost as long as pro- and mesonotum combined, slightly shorter than mesothorax, metafemora almost reaching to posterior margin of abdominal segment IV and metatibiae reaching posterior of abdominal segment VII. Anterodorsal carina of profemora elevated into a roughly wave-like lamella which is protruded into 10–11 broad, triangular teeth; the basal ones minute, median ones very prominent and apical ones decreasing in size. Posteroventral carina very minutely and sparingly dentate. Anterodorsal carina of protibiae raised and protruded into three prominent, irregularly rounded lobes in great distance to another; the median one largest. Occasionally there is another more minute lobe between the second and third one (Fig. 317). Meso- and metafemora with a broad triangular and dentate sub-basal lobe on the two outer ventral carina and a single enlarged tooth about 1/3 the way along posterodorsal carina; otherwise very minutely and sparingly serrate. Meso- and metatibiae with a prominent rounded median and apical lobe on posterodorsal carina and a rounded apical lobe on posteroventral carina (Fig. 322). Basitarsi as long as following three tarsomeres combined, all carinae more or less distinctly elevated and smooth.

Nymphs: Body more slender, head more prominent and armature of legs more decided than in adults. Abdominal tergites II–VII with a more decided posteromedial tubercle and lateral lobes of VII more slender than in adults, occasionally with lateral lobes on tergite VI as well. General colouration of body and legs dark greyish brown with irregular pale greyish speckles and markings on head, mesonotum, median segment, single abdominal segments and legs which generally correspond to those in the adult ♀ described above. Head occasionally with a bold, wedge-shaped, greenish white marking and metanotum occasionally with a distinct white posteromedial spot.

♂♂ ( Fig. 97): Medium sized (body length 109.5–136.0 mm) and very slender (maximum body width 2.5 mm) for the genus, with long alae (48.7–58.5 mm). General colouration of body and legs greyish, yellowish or greenish mid brown, ventral surface of abdomen to a various degree furnished with whitish speckles. Meso- and metasternum dull green, mesopleurae with a greyish white spot close to posterior margin. Lateral margins of tergite IX with a bold ± decided white longitudinal band in posterior portion. Sternum IX with a white lateral spot. Cerci greyish mid brown. Anterior margin of tegmina and basal third of anterior margin of alae with a longitudinal white band which is interiorly bordered by a fine black line (the latter very indistinct on alae). Costal region of alae slightly lighter brown than tegmina, anal region transparent greyish brown. All veins mid brown, transverse veins very indistinct. Meso- and metafemora and all tibiae with faint whitish transverse bands, bases of all femora pale brown. Complete armature of legs black. Meso- and metabasitarsus whitish basally. Eyes dark brown. Antennae yellowish to reddish mid brown.

Head (Fig. 295): Elongate, oval, almost 2.5x longer than wide, narrowing from eyes towards posterior margin, vertex flat. Between bases of antennae with a distinct transverse impression, and two very slight impressions between the eyes. Eyes prominent, strongly convex and projecting hemispherically from head capsule; their length contained almost 3x in that of cheeks. Antennae reaching about half way along median segment, with 27 segments. Scapus dorsoventrally flattened, parallel-sided, 2.5x longer than wide. Pedicellus 1/3 the length of scapus, spherical. Following antennomeres distinctly increasing in length, the 5 apical ones strongly shortened.

Thorax: Pronotum distinctly shorter and narrower than head, the anterior portion very slightly narrowed. Median transverse depression distinct but short and not reaching lateral margins of segment. Mesothorax about 2.8x longer than head and pronotum combined. Mesonotum with a very fine and indistinct longitudinal median carina and sparsely set with a variable number of minute granules, occasionally with a few slightly enlarged granules along the lateral margins. Mesopleurae with a longitudinal row of minute granules. Mesosternum with a faint longitudinal median carina, metasternum smooth. Tegmina elongate, oval and with a distinct roundly conical central hump. Alae ± reaching posterior margin of abdominal tergite V.

Abdomen: Median segment 2.5x longer than metanotum, 4x longer than wide and slightly tapered towards the posterior. Segments II–VI about 6.5x, VII 5x longer than wide. V occasionally with a very minute transverse posteromedian tubercle. Sternites II–VII smooth. Tergite VIII 3/4 the length of VII, 3x longer than wide, slightly widening towards posterior margin and strongly convex. IX slightly longer than VIII, constricted medially and 4x longer than wide. Anal segment distinctly shorter than IX, strongly keeled and laterally compressed. Semi-tergites short with the apex acutely triangular and the tip pointed and gently downcurving (Fig. 207). Interior surfaces apically set with several small black teeth. Cerci short, round in crosssection and tapered towards a pointed tip, not reaching apex of anal segment. Poculum strongly convex and cup-like with the centre moderately conically elevated; reaching about half way along tergite IX.

Legs: All very long and slender, profemora a little longer than combined length of head, pro- and mesothorax, mesofemora a little longer than pro- and mesonotum combined, metafemora almost reaching posterior margin of abdominal segment V and metatibiae projecting over apex of abdomen. Anterodorsal carina of profemora with 10–16 ± prominent, black triangular serrations; these occasionally strongly enlarged and saw- or lobe-like (Fig. 337). Posteroventral carina set with a similar number of considerably smaller triangular teeth. Anterodorsal carina of protibiae smooth or sometimes sparingly serrate; occasionally with three more or less distinctly enlarged teeth. Posteroventral carinae sparingly serrate, anteroventral carina smooth. Two outer ventral carinae of meso- and metafemora minutely serrate, dorsal carinae each with only 3–7 minute teeth. Medioventral carina with 4–8 very minute spines. Occasionally the mesofemora posses a distinctly enlarged, roundly triangular sub-basal lobe on the antero- and posteroventral carinae and two or three enlarged teeth about one quarter along the dorsal carinae. An enlarged, triangular lobe may sometimes also be present about one third the way along the posterodorsal carina of the metafemora. Ventral carinae of meso- and metatibiae minutely and sparsely serrate, dorsal carinae with only a very few minute teeth. The posterodorsal carina forming a ± distinct bi-dentate lobe at the apex of tibia and occasionally bears a ± prominent and broad, triangular lobe near the middle. Probasitarsi almost 1.5x longer, meso- and metabasitarsus about as long as remaining tarsomeres combined, all carinae gently elevated and smooth.

Variation: Although only a very few specimens are know, Ph. tirachus is seen to exhibit considerable intraspecific variability which concerns to both sexes. The quite mutilated and incomplete ♂ in ZSMC is remarkable for the very prominent armature of the legs (Fig. 337), but is otherwise a typical specimen. The teeth of the anterodorsal carinae of the profemora are distinctly enlarged and saw-like, the mesofemora bear a large basal lobe on both the antero- and posteroventral carinae and have two or three distinctly enlarged teeth about one quarter the way along the dorsal carinae. The left metafemora exhibits a large triangular lobe about one third the way along the anterodorsal carina.

The two ♀♀ nymphs in MNHU alone, clearly show the large range of variability within ♀♀ of this species. One specimen has the complete leg armature strongly reduced (Fig. 316) while it is remarkably developed in the other. The latter specimen has the anterodorsal carina of the profemora dilated into three prominent, triangular teeth and the anterodorsal carina of the protibiae has the two more apical lobes prominently enlarged and foliaceous (Fig. 317). All of the lobes of the mid and hind legs are strongly enlarged and ± foliaceous. The lateral lobes of abdominal tergite are broader than the body width and there are two slightly smaller posterolateral lobes on tergite VI in this specimen. The latter lobes are lacking and those of tergite VII decidedly less developed in the other.

Eggs (Figs. 155–156): There is a glass-tube next to the ZMUH ♀ containing three eggs, one of which has been taken from the ovipositor and hence fully developed. Unfortunately, this unique sample has the capitulum broken off.

Meduim-sized, capsule very gently laterally compressed and surrounded by a very faint, blunt bulge, beginning and ending at the operculum. Seen laterally the capsule is almost circular with bold impressions on both sides of the median line, anterodorsally near the operculum and ventrally close to the polar-area. Capsule surface densely granulated. General colouration of capsule, micropylar plate and operculum blackish brown. Micropylar plate broad, distinctly raised from capsule and shaped like an inverted “Y”. All the extensions moderately long and rounded apically. Micropylar cup very small, knob-like and placed in centre of posteromedian gap of the plate. Median line indistinct. Operculum slightly oval, flat. Capitular stalk short, whitish.

Measurements [mm]: length 4.0, width 3.7, height 3.9, length of micropylar plate 2.9.

Comments: Westwood (1859: 75) originally described Phibalosoma tirachus from a unique ♂ in OXUM and provided a nice illustration of the HT ( Westwood, 1859: pl. 37: 3). The HT was so far untraced and not included in the numbered type-collection of OXUM. A ♂ in the main collection with the data “Cantor, Malacca ” (= Peninsular Malaysia) however matches exactly the locality, description and illustration provided by Westwood, and hence undoubtedly represents the so far untraced HT of Phibalosoma tirachus Westwood.

The MNHU collection contains four ♂♂ from Java, which were erroneously identified as “ Pharnacia hypharpax Westw. ” by K. Günther, and there is a further ♂ from Java in ZSMC. Although from Java, examination of these specimens and comparison with the HT from Peninsular Malaysia have clearly proven all five specimens to represent Ph. tirachus . Along with the ♂♂ in MNHU there are two large ♀ nymphs which bear exatly the same data. Comparison with the ♂♂ has proven these to be the opposite sex. Furthermore, these are undoubtedly identical to Clitumnus irregularis Brunner v. Wattenwyl, 1907, which consequently becomes a junior synonym of Pharnacia tirachus (Westwood) (syn. nov.) .

Brunner v. Wattenwyl (1907: 195) described Clitumnus irregularis based on a nymph from Buitenzorg [= Bogor], Java in ZMAS and stated the body length to be 140.0 mm. Brock (2006: 55) stated no type specimens of C. irregularis were traced in ZMAS and that the specimen was apparently retained in NHMW. Indeed, there are two ♀♀ nymphs from Java in NHMW which are clearly this species. However, due to Brunner v. Wattenwyl (1907) did not mention any material from Vienna and the specimens are considerably shorter than the length recorded for the type (<100.0 mm), they are definitely not the type specimens.

One of the ♀ nymphs from Java in MNHU bears a hand-written note by K. Günther which states: “Die Spezies ist als Larve beschrieben und als solche in vielen Sammlungen; die erwachsenen Tiere dazu dürften der auch in diese Gattung gehörige Eucarcharus inversus Br. v.W. oder Pharnacia semilunaris Redt. Sein ” [This species was described from a nymph and is represented as such in numerous collections; the adults might be represented by Eucarcharus inversus Br. v.W. or Pharnacia semilunaris Redt. , which belong in the same genus]. This shows at least Günther to have identified the generic position of Clitumnus irregularis . The ZMUH contains an adult ♀ from Perak ( Peninsular Malaysia), the only one known so far, and a glass-tube with three eggs which served for the descriptions above .

Ph. tirachus is apparently rare in Peninsular Malaysia but appears to be not uncommon and rather widely distributed in Java. Seow-Choen (2000: 38, pl. 97) provided an illustration of the ♂ and cited body-lengths of 115.0–136.0 mm .

Distribution (Fig. 378): Peninsular Malaysia ( Malacca; Perak & Penang Hills, 1800–2500ft.) and Java (Bogor; Mount Gede: Tjibodas & Kendeng Mountains 3000–4000 ft.).

Number of specimens examined: 13