Phryganistria heusii (Hennemann & Conle, 1997) Hennemann & Conle, 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 : 209-212

Phryganistria heusii (Hennemann & Conle, 1997) comb. nov.

( Figs. 127–128, 190–191, 277–279, 282–283, 288, 355, 359, 398)

Phobaeticus heusii Hennemann & Conle, 1997b: 505 , figs. 1–5. HT, ♂: N-Vietnam, Cuc Phuong, ex. Zucht P. Heusi 1996 (ZSMC, ex coll. FH, No. 0240-1); AT, ♀ (+ 4 eggs): N-Vietnam, Cuc Phuong, ex. Zucht P. Heusi 1996 (ZSMC, ex coll. FH, No. 0240-2).

Otte & Brock, 2005: 268.

Bresseel, 2007: 8.

Further material [7 ♀♀, 10 ♂♂, eggs]:

N-VIETNAM:

6 ♂♂, 6 ♀♀, eggs: ex Zucht: F. Hennemann 2002, Herkunft: N-Vietnam, Ninh Binh Prov., Nho Quan District , Cuc Phuong (coll. FH, No’s 0240-3 to 14, ED) ; 1 ♀, 4 ♂♂: ex Zucht: F. Hennemann 2002, N-Vietnam, Ninh Binh Prov., Nho Quan District, Cuc Phuong (coll. OC) .

Diagnosis: Very closely related and certainly the sister-taxon of Ph. grandis Rehn, 1906 , with which it is sympatric in Northern Vietnam, but differing by: the more robust body; relatively shorter and more robust legs and tarsi as well as the slightly less globose head of both sexes. ♂♂ clearly differ by: the black profemora which have the basal portion pale straw and the posteroventral carina sparsely dentate; relatively larger eyes; broader apical portion of the semi-tergites of the anal segment and distinctly shorter, more obtuse and conical cerci which clearly stay beyond the apex of the anal segment (Fig. 283). ♀♀ may be distinguished by: the posteromedian tubercle on abdominal tergites II–VI; shorter and more broader lobe-like spines of the praeopercular organ (Fig. 282) and much more shallow posteromedian excavation of the anal segment (Fig. 288). Eggs differ from those of Ph. grandis by the larger dimensions, less ovoid capsule and relatively larger, more elongate micropylar plate (Figs. 188–189) .

Etymology: Dedicated to Peter Heusi (Uster, Switzerland), who first imported culture-stock of this magnificent species to Europe and provided the type specimens.

Description: ♀♀ ( Fig. 127): Very long (body length 239.0–293.0 mm) and slender species (maximum body width 7.0– 9.5 mm), complete surface smooth and slightly glabrous. General colouration of body and legs variable, ranging from more or less plain pale to dark brown or green. Abdomen in particular ± decidedly furnished with small black or brown speckles. Lateral surfaces of head usually with an indistinct longitudinal dark brown stripe above the eyes, which consists of numerous small dark brown speckles. Eyes dark reddish brown. Antennae brown with ventral surfaces except scapus and pedicellus black.

Head (Fig. 278): Oval, 1.3x longer than wide, broadest behind the eyes and slightly narrowed posteriorly, vertex almost flat and with a well decided impressed coronal line. Posterior margin usually with a further longitudinal, sub-parallel impression. A deep, transverse impression between the bases of antennae. Eyes of aver- age size, circular, and projecting hemispherically; their length contained almost 3x in that of cheek. Antennae almost reaching posterior margin of mesonotum, consisting of about 38 antennomeres. Length of antennomeres first increasing in length, then decreasing owards apices of antennae. Scapus roundly rectangular, dorsoventrally compressed and about 2.5x longer than wide. Pedicellus slightly spherical, 1/3 the length of scapus. Third antennomere cylindrical, narrower but slightly longer than pedicellus.

Thorax: Pronotum almost as long but conspicuously narrower than head, about 1.7x longer than wide, slightly gradually broadening towards the posterior. Anterior margin gently arcuate and followd by a transverse furrow; dorsal surface otherwise with an impressed longitudinal median line. Median transverse depression distinct, slightly curved and almost reaching lateral margins of segment; median line clearly visible. Mesothorax about 2.7x longer than head and pronotum combined, mesonotum parallel-sided. Metathorax slightly broadened posteriorly, metanotum 4x longer than wide with posterior margin slightly broader than anterior margin. Sterna and pleurae smooth.

Abdomen: Median segment slightly longer than wide, rectangular, slightly more than ¼ the length of metanotum. Segments II–VI increasing in length, II 2x, VI 3.5x longer than wide. Tergite VII ¾ the length of IV with lateral margins gently rounded posteriorly. Tergites II–VIII with a transverse posteromedial tubercle, which is most prominent on IV–VI. Praeopercular organ formed by a pair of prominent, triangular lobe-like spines at posterior margin of sternum VII (Fig. 359). Remaining sternites smooth. Tergite VIII 2/3 the length, 2.5x longer than wide, strongly convex, parallel-sided and slightly narrower than VII. IX a little more than half the length of VIII, 1.3x longer than wide and strongly convex. Anal segment slightly longer than IX flattened and slightly broadening posteriorly, with a fine longitudinal median carina and a wide and shallow excavation poseromedially (Fig. 288). Supraanal plate small, transverse and slightly projecting over apex of anal segment. Cerci small and conical, finely bristled. Gonapophyses up-curving and almost reaching tip of subgenital plate. Subgenital plate keeled, boat-shaped and at best very slightly projecting over posterior margin of anal segment (Fig. 282).

Legs: All very long and moderately slender. Profemora about as long as head, pro- and mesonotum combined, mesofemora Anacardiaceae shorter than mesonotum, metafemora reaching about 1/3 the way along abdominal segment V and metatarsi slightly projecting over apex of abdomen. Anterodorsal carina of profemora with 11–18 prominent, acutely triangular serrations which decrease in size towards apex of femur, posterodorsal carina set with 3–5 very small teeth. Posteroventral carina with 17–20 medium-sized but pointed teeth. Posteroventral carina of protibia sparsely and minutely serrate, remaining carinae unarmed. Two outer ventral carinae of meso- and metafemora armed with 13–19 pointed triangular teeth of average size, dorsal carinae each with only 2–5 minute but acutely pointed teeth. Medioventral carina with a longitudinal row of 10–18 minute spines. All ventral carinae of meso- and metatibiae densely serrate, dorsal carinae with only a few rather small teeth. Posterodorsal carina rounded and bi-dentate apically. One specimen (coll. FH, No. 0240-5) has the posterodorsal carina very gently but widely raised and terminating in a small tooth pre-medially. Probasitarsus elongate and with the dorsal carina gently raised and rounded apically, slightly longer than remaining tarsomeres combined; all carinae smooth. Meso- and metabasitarsi slightly longer than following three tarsomeres combined, dorsal carina gradually raised and conspicuously rounded at the apex; ventral carinae set with a few minute teeth.

♂♂ ( Figs. 128): Very long (body length 206.0– 250.5 mm) and rather robust for the genus (maximum body width 8.0–9.0 mm), the meso- and metafemora conspicuously swollen and broader than corresponding tibiae. Body surface entirely smooth and glabrous. General colouration of body, mid and hind legs pale to mid ferruginous or yellowish brown. Greater portion of the mesonotum except anterior and posterior margin as well as the anterior ¾ of the metanotum covered by a washed malachite green or creamish grey marking. Profemora black except for the compressed basal portion and extreme apex both of which are pale straw; the latter occasionally with a slight pinkish wash. Protibiae dark brown and marbled with black ventrally. Eyes greyish or reddish brown. Scapus and pedicellus of same colour as body. Remaining tarsomeres very dark brown dor- sally, black ventrally and becoming black towards apex of antennae. Spination of legs dull red with black tips.

Head (Fig. 279): Generally as in ♀♀, but more decidedly narrowed towards the posterior; posterior margin with three small, longitudinal impressions. Transverse impression between bases of antennae less distinct. Eyes very prominent, circular and projecting hemispherically; their length contained only about 2.3x in that of cheek. Antennae generally as in ♀♀ but relatively longer and slightly projecting over posterior margin of median segment.

Thorax: Pronotum generally as in ♀♀, but anterior margin more distinctly narrowed. Mesothorax very elongate, cylindrical and more than 3x longer than head and pronotum combined. Mesothorax slightly broadened posteriorly, the mesonotum gently widened in that section; a little more than 3x the length of head and pronotum combined. Metathorax constricted medially, metanotum 6x longer than wide and widened in posterior portion. Meso- and metasternum smooth, the first strongly convex.

Abdomen: Median segment, a little more than ¼ the length of metanotum, 1.5x longer than wide and trapezoidal being gently broadened towards the posterior. Segment II about 1.8x longer than median segment but shorter than following. II–VI distinctly constricted medially and increasing in length, II 3.3x, VI 5x longer than wide. Tergite VII 3/5 the length of VI, slightly broader than previous and widened posteriorly. VIII strongly convex, slightly longer than wide and conspicuously broadening towards posterior margin; broadest segment. IX slightly shorter than VIII and tapered towards the posterior and with a longitudinal impression laterally. Anal segment laterally compressed, strongly tectiform and carinate dorsally. Semi-tergites roughly triangular, very broad basally and gradually tapered in apical half, the apices rounded (Fig. 283). Interior surfaces swollen apically and densely armed with minute black teeth. Cerci stout, conically tapered towards an acute tip and staying clearly beyond apex of anal segment. Poculum strongly convex, cup-like with a blunt rectangulate hump basally and reaching to posterior margin of tergite IX.

Legs: All very long and rather robust, armature generally as in ♀♀. Profemora almost as long as head, pro- and mesonotum combined, mesofemora about as long as mesonotum, metafemora reaching almost posterior margin of abdominal segment V and metatibiae projecting considerably over apex of abdomen. Profemora with serrations of anterodorsal carina smaller than in ♀♀ and the posteroventral carina just sparsely and rather minutely dentate. Protibiae at best with a few minute teeth on posteroventral carina, otherwise unarmed. Meso- and metafemora prominently swollen and considerably broader than corresponding tibiae. Two outer ventral carinae each with a very prominent and acute, black dagger-like spine sub-apically (Fig. 277); this is sometimes accompanied by one or two conspicuously enlarged spines on metafemora. Dorsal carinae of meso- and metafemora at best with 1–3 minute teeth and those of corresponding tibiae very sparsely and minutely dentate. Probasitarsus very elongate and slender, almost 1.5x longer than remaining tarsomeres combined and with the dorsal carina very gently raised; all carinae smooth. Meso- and metabasitarsus slightly longer than remaining tarsomeres combined, otherwise as in ♀♀ but dorsal carina less decidedly raised.

Eggs (Fig. 190–191, 355): Large, capsule oval in lateral aspect and slightly laterally compressed, oval in cross-section. Capsule with a very shallow keel on dorsal and ventral surfaces and polar-area, beginning and ending at the operculum. Capsule surface slightly shiny and very minutely rugulose and granulated (70x). General colouration of capsule and micropylar plate creamish grey-brown, operculum blackish brown. Micropylar plate large, elongate and covering about ¾ the length of capsule, tapered towards anterior end and with a wide gap posteromedially. Outer margin of plate dark brown. Micropylar cup placed in the gap of plate, small, dark reddish brown. Median line slightly raised and short, not considerably projecting over posterior margin of plate. Operculum slightly cordiform and convex. Capitulum prominent, slightly conical and with several deep lateral impressions; greyish or reddish mid brown. Stalk obvious, whitish.

Measurements [mm]: Length including capitulum 5.5–6.2, length 4.9–5.8, width 3.0–3.2, height 3.9–4.0, length of micropylar plate 4.1.

Comments: Hennemann & Conle (1997b: 505) originally described Phobaeticus heusii from an F1-generation captive reared ♂ HT, ♀ AT and four eggs (PT’s). The original eggs were obtained from a Nature Reserve Project in Cuc Phuong , Nho Quan District , Ninh Binh Province (about 100 km south of Hanoi ) by Peter Heusi (Uster, Switzerland) in 1996. The type specimens have subsequently been deposited in ZSMC .

With a maximum recorded body length of 250.5 mm the ♂♂ of Ph. heusii represent the longest of all known extant male Phasmatodea (see Hennemann & Conle, 1997b: 508) even being the world’s longest known male insect. ♀♀ reach overall lengths of almost 500.0 mm if legs are included, a ♀ in coll. FH (No. 0240-3) measuring 479.0 mm from the tip of the protarsi to the tip of the hind tarsi, thus being among the world’s longest extant insects.

♂♂ occur in two distinct colour morphs, either having the dorsal surface of the mesonotum and anterior ¾ of the metanotum washed malachite green or creamish grey.

Eggs were imported along with stock of Tirachoidea jianfenglingensis ( Bi, 1994) by P. Heusi ( Switzerland) on at least two occasions. In captivity in Europe Ph. heusii has proven rather difficult to maintain in a stable culture for more than a few generations, but it still is successfully reared by several enthusiasts why it was recently included on the Phasmid Study Group culture-list as PSG 277. Oak ( Quercus spp. , Fagaceae ) and bramble ( Rubus spp. , Rosacea) are accepted as alternative foodplants and very large cages are necessary to ensure successful moulting of large nymphs. Notes on breeding were provided by Bresseel (2007).

Distribution (Fig. 398): Northern Vietnam (Ninh Binh Province: Nho Quan District, Cuc Phuong).

Number of specimens examined: 19