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Volume 82, 1954-55
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A New Genus and Species of Phasmidae from New Zealand

[Read before the Wellington Branch, October 28, 1953: received by Editor, October 29, 1953.]

Summary

Tectarchus, a new genus of Phasmidae, and for new species are described.

Phasmids, or “Stick Insects” as they are popularly called, are common throughout New Zealand from sea level to quite high altitudes, but with the exception of Hutton's two early papers in the “Transactions and Proceedings of the New Zealand Institute” (Vols. XXX and XXXI), very little has been published concerning them. Over the past fifteen years I have been studying the habits of these interesting insects and collecting specimens of them from all over the country. This paper, which is presented as the forerunner of a series dealing with the Phasmidae of New Zealand, describes a new genus containing four new species of what might popularly be called “Ridged-back Stick Insects”. The epithet of “Ridged back” stems from the characteristic shape of the body in which the sides of the thoracic and abdominal segments slope away from a central dorsal longitudinal ridge rather like the sides of a ridged roof.

Genus Tectarchus nov.

Medium sized species, carinate dorsally. rounded ventrally, with the cuticle more or less tuberculated; the operculum reaching to the posterior border of Abd. VIII or just beyond; the terminal tergite in the male with a pair of very large internal teeth on each side.

Females are immediately recognized by the flattened sloping sides of the body, which extend “roof-like” from the mesothorax to the tip of the abdomen, meeting along the mid-dorsal line in a distinct ridge. This ridged appearance is not so obvious in the males, whose slender match-like bodies do not lend themselves to such morphological differentiation. Close examination, however, reveals that the male body is ridged at least on the mesothorax and anterior part of the abdomen, in some species the ridging flattens out towards the posterior. This dorsal ridge, in both males and females, is generally marked on either side by an irregular row of small tubercles. The head and prothorax are not ridged in either sex, being instead more or less flat or rounded, generally tuberculated. and, particularly on the prothorax, variously sculptured. In both sexes the trunk is rounded on the ventral surface, tuberculated, and often with longitudinal ridges; the cuticle is finely granulated and more or less coarsely and irregularly tuberculated; the tubercles often surmounted by very minute setae or hairs; the lateral edges of both terga and pleura usually thickened, the former more noticeably so. A longitudinal tuberculated ridge, which arises on each side of the prothorax, passes along each side of the body to the tip of the abdomen, being most distinct on the abdomen and situated about one-third down the terga from

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the mid-dorsal line; sometimes between this ridge and the lateral margins of the terga are one or two additional similar ridges, but these, when present, are never so prominent as the first mentioned ridge. On the posterior margin of each segment the mid-dorsal longitudinal ridge is elevated into a more or less prominent hump, or tubercle, which may bear several very small hairs and a distinct black coloured dot. The eusternum and sternellum of Th. I are square to rounded, and characteristically tuberculated for each species; the eusternum of Th. II always bears several extrá large tubercules in both sexes. The antennae are short, comprising about 20 segments, of which the basal two are elongated, broadened laterally and compressed dorso-ventrally, usually sculptured and tuberculated above but sculptured and hairy below; the remaining segments cylindrical, mostly short and clothed with whorls of fine short setae; the apical segment is usually the longest segment of the antenna, and that segment which bears the dorsal sensory organ is also elongated. There is no indication of subsegmentation of the metathorax, either dorsally or ventrally, and all nine abdominal tergites are visible from above. The cerci are short foliaceous and hairy. In the female the operculum reaches to the posterior border of Abd. VIII, or, at the most, just slightly beyond. It is boat-shaped, carinate ventrally and rounded or pointed apically.

In the male the terminal tergite, viewed from the side, is rectangular in shape with its posterior ventral corner rounded and swollen internally where it bears a pair of enormous, heavily chitinised, inwardly directed teeth; there are no other teeth. This swollen portion may extend antero-dorsally across the external surface of the tergite as a broad raised area. The posterior and ventral margins of the tergite always with at least some short setae but not produced at all to form claspers.

All the femora and tibia are narrow and flattened above, with their sides sloping away to a broader ventral surface; the margins of the dorsal surface marked by tubercles or fine setae; the ventral surface prominently carinate centrally with its margins thickened and invested with rows of small tubercles or fine setae. Each femur apically rounded above and bearing a pair of small inferior foliaceous lobes, one to each side. Each tibia somewhat truncated apically, square above but with a pair of inferior spines, one to each side. The tarsi five segmented, flattened below, very strongly carinate above, very hairy; the basal segment longer than any of the others, usually approximately as long as the others together; the penultimate segment very short; each segment with an euplantulum; the distal segment bearing two claws and an arolium.

Type species for the genus: Tectarchus diversus n.sp.

All the species of this genus are very similar in general facies and can only be easily distinguished systematically by making use of such detailed morphological features as the shapes and tuberculation of the tergum, eusternum and sternellum of Th. I, the genitalic and terminal abdominal structures and the antennae. The shapes of the eusternum and sternellum vary somewhat within each species, and this character can be used as a rough guide only; the tuberculation of these structures is, however, a more reliable systematic guide. For convenience, the more clearly diagnostic features have been italicised in the description of each species.

Tectarchus is probably closest related to Hemipachymorpha Kirb. which is also “ridge-backed” and comes from South Africa. Hemipachymorpha, however,

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is carinate on the ventral surface as well as on the dorsal surtace, whereas Tectarchus is rounded ventrally without carinae. In addition, the operculum extends further towards the posterior in the South African genus than it doe; in the New Zealand one.

Tectarchus diversus n.sp. Plate 7, Figs. 1 and 2; Plate 8, Figs. 1 and 2, 4 and 8; Plate 9, Figs. 1 and 5.

Colour: Alive, the female is normally entirely either a bright green or a medium brown with the anterior faces of the basal portions of the fore femora pink to reddish; the joints of the legs and the dorsal longitudinal ridge of the body often tinged with red. Mottled forms often occur in which dark brown or black rectangular markings overlay a fawn ground colour, sometimes with shadings of green towards the posterior; mixed forms partly green and partly brown, or in two shades of brown, also occur, in which the two colours usually form a longitudinal colour pattern. Brown specimens vary from a medium sepia to fawn or russet; green specimens from a dull blue-green to bright grass-green. Antennae usually ochreous, often yellow towards their tips. Legs either green or brown, corresponding to the body colour, with the bases of the fore femora pink and often with the basal joints of the other femora tinged with pink; the legs are otherwise plain coloured or banded with deeper greens or browns, and the tarsi are often pinkish or ochreous.

The male is usually entirely a pale ochreous brown on both body and legs, seldom green, and has the antennae yellow; a narrow longitudinal orange stripe down each side of the mesothorax and metathorax and a similar coloured transverse band across the posterior prothoracic border. The bases of the fore femora are a smoky pink, the bases of the other femora suffused with dark reddish-brown, the tarsi ochreous white. Generally there is a suffusion of yellow dorsally on Abds. VII, VIII and IX, with the cerci pale pink.

Body: Length of female 6.75 cm. with the antennae an additional 1.2 cm.; the male 5.25 cm. with the antennae 1.2 cm. extra; the head, Th. I, II and III in the female related as 6:4:12.10; in the male as 7:5:19:19; abdominal segments more or less subequal in length, but in the male only very much broadened on VII and VIII. Cuticle very finely granular, evenly and fairly densely covered with small tubercles, both dorsally and ventrally; many of these tubercles are surmounted by a very minute bristle; five to seven larger deeper coloured tubercles occur as a row ventro-laterally along each side of the mesothorax. In the female, the dorsal surface of the head shows no sculpture apart from a shallow median dorsal longitudinal groove, deepening posteriorly, and a shallow crescent-shaped depression behind the inner margin of each antenna. In the male, the longitudinal groove is paired. Antennae in female each of 20 segments, of which the basal three, the ninth and the apical are all much longer than the rest; male antennae each of 19 segments, of which the basal three, the eighth and the terminal are the longest; the ninth or eighth segment respectively bears a large dorsal basal sensory swelling; all segments moderately clothed with short setae. Prothorax broadly and shallowly emarginate across anterior border, only slightly rounded on the shoulders, distinctly sculptured, with a deep mid-dorsal longitudinal groove flanked on either side by a thickened ridge surmounted by tubercles and crossed, just past mid-way, by a short deep transverse furrow;

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just inside the anterior lateral border of the prothoracic tergum, on each side, is a shallow pit which passes posteriorly into a sulcus; this sulcus runs back to the transverse furrow where it bends sharply forward again as a V-shaped furrow that connects with a fovea in the centre of each side of the anterior margin. Lateral margins of the prothorax noticeably thickened and tuberculate. The posterior border of each segment, mid-dorsally, more or less raised into a low tubercle bearing a black mark. The eusternum of Th. I, only sparsely and finely tuberculate, truncate or emarginate in front, faintly emarginate with a median groove posteriorly. Sternellum curved or truncate in front, bearing fairly large tubercles, with its edges only very slightly thickened but coarsely tuberculated. The operculum of the female deep dorso-ventrally, rugose, carinate with no basal tubercle on the carina; the apex more or less triangulate and pointed; rugosities, carina and edges of operculum all bearing minute setae. Cerci three times as long as paraprocts, foliaceous and coarsely tuberculate with each tubercle surmounted by a seta. The subgenital plate of the male faintly carinate, rugose, rounded apically with a suggestion of a shallow notch where the ventral carina meets the apex, this carina with a large, blunt spine-like tubercle about mid-way along its length; the lateral margins and rugosities thickened, and both these and the carina sparsely clothed with very short setae.

Legs as described under the generic description with all margins or carina clothed with minute setae. Occasional spine-like tubercles occur irregularly on all femora and tibiae; they often vary between the two sides of the same individual insect and are of no systematic importance.

Localities: Akatarawa Saddle; Silverstream, South Karori; Wilton's Bush, Wellington; Johnston's Hill, Karori; Days Bay; Mt. Ross, Wairarapa; Orongorongo; Balloon Saddle, Mt. Arthur Tableland; Leslie Valley; Kennedy's Bush, Banks Peninsula; Coll. J. T. S.; Paremata; Coll. J. Ardley; Miramar Reserve, Wellington; Picton; Upper Maitai, Nelson; Coll. Graeme Ramsay.

Found mostly on astelias on trees in the bush; also on celery-leaved pine and occasionally on lawyer and manuka.

Type and Paratypes in the Dominion Museum Collections. Paratypes in the Author's Collection and Graeme Ramsay's Collection.

Tectarchus ovobessus n.sp Plate 7, Fig. 3; Plate 8, Figs. 3 and 5; Plate 9, Fig. 2.

Colour: In life the colour usually entirely ochreous to orange brown or fawn, occasionally green, with the cuticular tubercles often tinged with orange-red, bases of fore femora dark brown; leg segments often with their apices tipped with red; the posterior segmental margins each with either a black or very dark brown spot medio-dorsally and another on each side; tarsi and tips of antennae also dark brown.

Body: Length, 5.75 cm. with the antennae an additional 1.1 cm. The head, Th. I, II and III related as 5:3:10:9, abdominal segments more or less subequal. Cuticle very finely granular and sparsely tuberculate. Except on the sides of the prothorax the tubercles dorsally and ventrally are small and tend to be arranged in rows longitudinally, especially on the abdomen, where they occur mainly along the longitudinal cuticular ridges; some of the tubercles, as in diversus, have a minute bristle; laterally on each side of the prothorax is a row

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of four very large, deeply coloured tubercles, and this region has larger tubercles and is more heavily tuberculated than any other area of the body. Head much the same as in diversus, except that the post-antennal depressions are much deeper and form a pair of narrow elongated fovea. Antennae in female with 17 segments in which the basal three, the sixth and terminal are all longer than the rest, the terminal being slightly longer than the basal; the sixth segment bearing the dorsal sensory organ; all segments moderately clothed with short setae, segments I and II only sparsely so dorsally. Prothorax similar to diversus but more sparsely tuberculate and with the anterior lateral shallow pit and sulcus almost obliterated; the deep anterior central fovea of each side passes back as a deep sulcus to the transverse groove, deepening midway and at its posterior extremity in each case into a deep elongated fovea; this sulcus with its three fovea forms a line parallel with the lateral tergal margin. The mid-dorsal longitudinal ridge is more strongly developed than in diversus, being almost carinate. The eusternum of Th. I, almost devoid of tubercles and with squarish anterior shoulders and a broad median triangular truncated projection; posterior margin slightly emarginate: the sternellum with a few large tubercles, rounded along anterior margin and with its lateral margins thickened and coarsely tuberculate. Operculum shallow dorso-ventrally, carinate, apex rounded, with a faint heavily chitinized point at centre; the ventral carina only sparsely provided with setae and expanded anteriorly to form a small basal swelling; surface of the operculum slightly rugose, especially basally, and with occasional very minute tubercles; the lateral margins not noticeably thickened and without any setae. Cerci only twice as long as the paraprocts, foliaceous and sparsely clothed with occasional short hairs and shorter setae.

Legs as in T. diversus.

This species is known only from the female, and all efforts to find a male, either by collecting in the field or by rearing, have been fruitless.

Localities. Lake Waikaremoana, and throughout Urewera Country to altitudes of 3,200 feet, on astelias; Kennedy's Bush, Banks Peninsula, on manuka and lawyer; Te Aroha Mountain to 3,000 feet altitude, on astelias and kiekie; Mt. Ross, Wairarapa, 3.000 feet altitude, on astelias and lawyer; Coll. J. T. S.

Types and Paratypes in Dominion Museum Collections. Paratypes in Author's Collection.

Tectarchus semilobatus n.sp. Plate 7, Fig. 4; Plate 8, Figs. 6, 9 and 11; Plate 9, Figs. 3 and 6.

Colour. In life the female a pale fawn ground colour overlaid with a fine mottled pattern of brownish grey; Abds. VII and VIII whitish, Abd. IX dark brownish grey; legs fawn cross branded with brownish grey, the bases of the fore femora pink, those of the other femora yellow; antennae pale creamy white cross banded with brown. The male a deeper fawn ground colour suffused with greyish brown on the anterior portions of each segment and with yellowish or red suffused over the sides of the thoracic and posterior portion of the first five abdominal segments; Abds. VT, VII and VIII, whitish, tinged with yellow or pink; bases of fore femora pink, legs otherwise deep grey-brown, with the tarsi yellowish; head ochreous to pale pink, antennae white on basal segments, terminal

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three or four segments yellow, remainder reddish or orange; cerci ochreous or yellow in both sexes.

Body: Length of female, 5·3 cm., the antennae an additional 0·9 cm.; of male 4.6 cm. and 1·1 cm. respectively. Head, Th. I, II and III related as 9:6:18:16 in female, and as 7:4:17:16 in male. Abd. IV in female bearing small lateral and dorso-lateral foliaceous lobes. Abds. VII and VIII in male noticeably swollen and broadened. Cuticle finely granular and with many small, evenly arranged tubercles each surmounted by a minute bristle. Dorsal longitudinal ridge rounded somewhat anteriorly but strongly carinate posteriorly, and bearing numerous tubercles which are irregularly arranged, not in a row down each side as in diversus, and the posterior mid-dorsal tubercles on each segment are not well developed. On the ventral surface the cuticular tubercles are larger than those on the dorsal surface and sides. Dorsal surface of head tuberculate with, between the posterior borders of the eyes in the female only, a broad, low mound bearing a pair of large spine-like tubercles, one to each side; the median longitudinal groove of the head passes posteriorly between a further pair of moderately large tubercles. Antennae with 21 segments in female, the tenth bearing the dorsal sensory organ while the first three, tenth and terminal segments are all longer than any of the others. In the male the antennae have 21 segments and the dorsal sensory organ is on the eighth segment. In the male the dorsal surface of the head and the prothorax bears a narrow, deep, longitudinal groove. In both sexes there are at least three distinct longitudinal tuberculated ridges passing down each side of the body. The male generally is not so tuberculated as the female, and the tubercles are very small. Anterior border of prothorax slightly emarginate, with a small, curved projection at the centre, but with the margins extending out from this to the shoulders, quite straight. Prothorax very coarsely tuberculate, the anterior lateral depressions almost obliterated, the two anterior fovea well developed with a suggestion of a sulcus passing back from them on each side, but there are no other fovea; the zone bounded by the fovea and sulcus on each side and the transverse furrow behind in the female forms a distinct elevated area; in the male this area is demarcated by larger tubercles.

Eusternum of Th. I truncate or slightly emarginate anteriorly, posteriorly emarginate in female but truncate in male, and with median posterior groove, irregularly and very coarsely tuberculate. Sternellum of Th. I truncate posteriorly, triangulate, pointed anteriorly, in female, but truncate, in male, irregularly and very coarsely tuberculate. The sides of both the eusternnum and sternellum are markedly thickened and tuberculated. Operculum bluntly pointed apically, very deep dorso-ventrally, strongly carinate and rugose, the carina dividing anteriorly into a broad basal V-shaped ridge; the carina bearing many very small setae and the rugosities and the lateral margins also with similar though not so numerous setae; the lateral margins not noticeably thickened. Cerci short, foliaceous, very broad basally, and barely twice as long as the paraprocts.

Subgenital plate of male more or less rounded, faintly carinate along apical half, the apex blunt and rounded into the sides; margins faintly thickened, the basal half separated from the apical half by a broad, triangular foliaceous spine; the entire plate sparsely clothed with very short setae. Legs as in T. diversus.

Picture icon

Fig. 1—Tectarchus diversus female.
Fig. 2—Tectarchus diversus male.
Fig. 3—Tectarchus ovobessus female.
Fig. 4—Tectarchus semilobatus female.
Fig. 5—Tectarchus tuberculatus female.
Fig. 6—Tectarchus tuberculatus male.

Picture icon

Fig. 1—Tectarchus diversus n. sp. female left, male right.
Fig. 2—Tectarchus diversus operculum and apex of abdomen viewed from side (an egg is held in the operculum).
Fig. 3—Tectarchus ovobessus operculum and apex. of abdomen, viewed from side.
Figs 4–7—Female operculum cerci and paraprocts viewed from below:
Fig. 4—Tectarchus diversus (egg held in operculum)
Fig. 5—Tectarchus orobessus.
Fig. 6—Tectarchus semilobatus.
Fig. 7—Techarchus tuberculatus.
Figs 8–10—Male subgenital plate and apex of abdomen viewed from side.
Fig. 8—Tectarchus diversus.
Fig. 9—Tectarchus semilobatus.
Fig. 10—Tectarchus tuberculatus.
Fig. 11—Tectarchus semilobatus, operculum and apex of abdomen viewed from side.
Fig. 12—Tectarchus tuberculatus, operculum and apex of abdomen viewed from side with egg held in operculum.

Picture icon

Figs. 1–4—Eusternum and sternellum of prothorax and mesothorax.
Fig. 1—Tectarchus diverrsus female.
Fig. 2— Tectarchus ovobessus female.
Fig. 3—Tectarchus semilobatus female.
Fig. 4—Tectarchus tuberculalatus female.
Figs 5–7—Male subgenital plates viewed from below.
Fig. 5—Tectarchus diversus.
Fig. 6—Tectarchus semilobatus.
Fig. 7— Tectarchus tuberculatus.

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Locality: Kennedy's Bush, Banks Peninsula, on manuka and lawyer. Coll. J. T. S.

Type and Paratype in Dominion Museum Collection.

Tectarchus tuberculatus n.sp Plate 7, Figs. 5 and 6; Plate 8, Figs. 7, 10 and 12; Plate 9, Figs. 4 and 7.

Colour: The female alive is fawn to medium brown, with paler ochreous brown suffusions along dorso-lateral margins of head, dorsal surface of prothorax, anteriorly on mesothorax, and metathorax, and dorsally along the abdomen; a narrow longitudinal orange stripe along each side of the mesothorax and metathorax; antennae ochreous, yellow towards tips; legs pale ochreous-brown banded with darker brown; bases of fore femora bright pink. The male a deeper greyish brown with the posterior segmental margins banded with deep green, except for those of Abds. VII, VIII and IX; Abd. IX brick-red; Abds. VI and VII suffused with red dorsally; Abds. VII and VIII black dorsally, relieved by patches of white along the sides and posterior borders; antennae brown basally, becoming yellowish towards tips, and banded with greenish brown; legs ochreous yellow, banded with greenish brown, the bases of the fore femora and basal joints of the other femora all orange.

Body: Length of female 5.2 cm. with antennae 1·1 cm. extra; of male, 4.6 cm. with the antennae an additional 1·15 cm.; the head, Th. I, II and III related as 8:7:19:16 in the female, and as 6:5:16:15 in the male; the abdominal segments more or less subeqnal with, in the female, Abd. IV the broadest, either with or without small, sometimes minute foliaceous lateral expansions of the tergum, one to each side, after which the body narrows slightly to the posterior border of Abd. VI, becoming broader again on Abd. VII, then tapering slightly to the posterior; in the male the abdomen broadens considerably on Abds. VII and VIII, narrowing on IX to broaden again round the posterior margin. Cuticle finely granular and densely tuberculate all over, both dorsally and ventrally; more tuberculated than in any of the other species belonging to the genus; the tubercles mostly surmounted by a small spine. The dorsal surface of the head in the female normally with a large tubercle on each side behind each antenna and lying between the eyes; the male also with a distinct mid-dorsal longitudinal groove passing forward from the posterior border between the tubercles to a pair of fovea situated in a depression just behind the antennae. Head of the male otherwise almost smooth, but in female with a few scattered tubercles. Both male and female antennae with 21 segments, of which the terminal is the longest while the tenth is elongated and carries the dorsal sensory organ. Prothorax in female broadly emarginate in front, heavily tuberculate with a broad U-shaped raised anterior central area bounded on each side by a deep sulcus that terminates anteriorly in a narrow slit-like fovea and posteriorly joins the central transverse furrow; anterior marginal depressions absent; after the transverse furrow the sulcus of each side continues posteriorly to form a broad open inverted U-shaped pattern of grooves which open out rapidly on each side before they reach the posterior margin; the combined effect is not unlike a large “H” pattern, particularly in the male; a distinct mid-dorsal longitudinal groove traverses the tergum to terminate in a bunch of tubercles on the posterior margin. The mid-dorsal ridge strongly carinate with a narrow central longitudinal groove, and numerous

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tubercles on each side. In some specimens on most segments except the last three, there occurs on each side two large spine-like tubercles, one on the anterior margin and one on the posterior margin; these tubercles form a row along each side of the body about one-third down from the mid-dorsal line; on the thoracic segments there are often additional tubercles along the central portion of the segment. Other specimens show three distinct longitudinal tuberculated ridges down each side of the abdomen between the carina and the tergal margins. Eusteraum of Th. I truncate on both anterior and posterior margins, the sides considerably thickened and tuberculated, a suggestion of a median groove with a row of large, setaceous tubercles along each side; the sternellum rectangular, irregularly tuberculated with all the margins thickened and straight or nearly so. Operculum very deep, carinate, with the carina bearing numerous very short setae and terminating before the apex so as to leave a small, flat rounded but triangular apical lip; basally the carina divides into two very thick ridges: margins of the operculum thickened, setaceous; the body of the operculum only faintly rugose, more noticeably so towards the base and with small scattered tubercles. Cerci foliaceous, barely twice the length of the paraprocts and clothed with relatively long setae.

In the male the setae of the posterior region are much longer and more numerous than elsewhere on the body. The subgenital plate bears a large central setaceous tubercle which passes into a carina that extends from it to the apex. Apex rounded and slightly emarginate with the carina forming a slight central projection. margins faintly thickened with occasional short setae and hairs; basal portion of plate coarsely granular with occasional setae.

Leg s as in T. diversus.

Localities: Price's Bush, Banks Peninsula, on foliage of manuka and lawyer. Collected J.T.S.

Type and Paratypes in Dominion Museum Collections.