Myronides glaucus, Hennemann, 2021

Hennemann, Frank H., 2021, Stick insects of Sulawesi, Peleng and the Sula Islands, Indonesia- a review including checklists of species and descriptions of new taxa (Insecta: Phasmatodea), Zootaxa 5073 (1), pp. 1-189 : 49-53

Myronides glaucus n. sp.

( Figs. 19–20 )

HT, ♀: Indonesien, Peleng Island , VII.2011, local collector [ ZSMC, ex coll. FH, No. 0642-30] .

PT, ♂: ex Zucht: F,. Hennemann 2010/11, Herkunft : Indonesien, Peleng Island E of Sulawesi [ ZSMC, ex coll. FH, No. 0642- 29] .

PT, egg: ex Zucht: F,. Hennemann 2010/11, Herkunft: Indonesien, Peleng Island E of Sulawesi [ZSMC, ex coll. FH].

PT, 2 ♀♀: Indonesien, Peleng Island , VII.2011, local collector [coll. FH, No’s 0642-31 & 32] .

PT, 3 ♀♀: Indonesia, Peleng Isl. , Tataba, II-2020 , local collector [IMQC].

PT, ♀: ex Zucht A. & C. Bauduin 2008, Herkunft: Indonesien, Peleng Id., östl. Sulawesi, 2007 [coll. FH, No. 0642-1] .

PT, 2 ♂♂: ex Zucht A. & C. Bauduin 2008, Herkunft: Indonesien, Peleng Id., östl. Sulawesi, 2007 [coll. FH, No‘s 0642-2 & 3] .

PT, 7 ♀♀, 18 ♂♂, 1 ♀ penultimate instar, 24 eggs: ex Zucht: F. Hennemann 2010/11, Herkunft: Indonesien, Peleng Island E of Sulawesi (coll. FH, No‘s 0642-4 to 28 & E].

PT, 3 ♀♀, 6 ♂♂, 24 eggs: ex Zucht: F. Hennemann 2019–2021, Herkunft: Indonesien, Peleng Island E of Sulawesi (coll. FH, No’s 0642-33 to 41].

PT, 10 ♀♀, 18 ♂♂: ex Zucht: O. Conle 2010/11, Herkunft: Indonesien, Peleng Island E of Sulawesi (coll. OC, No’s 0546-1 to 28].

PT, 3 ♂♂: ex Zucht: F,. Hennemann 2019/20, Herkunft : Indonesien, Peleng Island E of Sulawesi [ NHMB] .

Etymology: The name ( glaucus lat. = cyan, teal, turquoise) refers to the pretty and very distinctive colouration of ♀♀ of this new species ( Figs. 20A–B ). Although there are two other colour morphs, the turquoise morph is the most common one.

Differential diagnosis: Both sexes of this new species differ from those of all other known species in the genus by the distinct node-like tubercles of the vertex and genae ( Figs. 19F, K ), ♀♀ furthermore differ by the slender shape and very prominent Preopercular organ, which is formed by two conical posterior projections on abdominal sternum VII ( Fig. 19C, E ), and ♂♂ can also be distinguished from other congenerics by the comparatively more slender hemi-terga of the anal segment, that in lateral aspect are tapered apically and have the posterior angle protruded into a long, acuminate projection which is almost ¾ the length of the basal portion ( Fig. 19G ).

Description: The colouration is described from live specimens. Provisional storage in ethanol discolours ♀♀ to drab or brown, which for instance is the case in the holotype.

♀ ( Figs. 19A , 20A–B ). Of medium size (body length 95.0– 110.5 mm), form slender and elongate for the genus with very distinctive colouration ( Fig. 19A ). Occurring in two distinct colour morphs. The more common turquoise morph has the body turquoise or cyan (darkening with age) with the head and prothorax mid to dull green. The legs are dull turquoise with washed black or dark purple mottling, all femora and tibiae having three pale turquoise annulae ( Figs. 20A–B ). The apical portions of the tibiae and the tarsi are brown. The cephalic tubercles are tipped with pale yellow and the eyes are contrasting bright yellow. The few granules of the meso- and metanotum are white and abdominal tergites II–VI have a small black spot at the posterolateral angle. The antennae from antennomere III onward are black and have each antennomere with the base pale cream. The rarer green morph differs from the turquoise morph in the following aspects: Body mid to dull green with the lateral margins of abdominal tergites II–VII white; head and prothorax yellow; legs basically yellowish green with the annulae dull yellow; bases of all femora with a slight reddish brown wash.

Head: Roundly rectangular, longer than wide, the vertex rather flattened and with the coronal line notably impressed. Vertex with 4–6 rounded coronal tubercles and occasionally with one or two smaller sub-orbital tubercles; genae with two prominent, blunt tubercles ( Fig. 19F ). Between the eyes with a pair of short, obtuse and gently anteriad directed spines and between bases of antennae with a two widely C-shaped, medially connected transverse grooves. Eyes almost circular, projecting hemispherically and their diameter contained 2x in length of genae.Antennae filiform and reaching to anterior of abdominal segment VI. Scapus strongly compressed dorsoventrally with the lateral margins gently deflexed and weakly rounded, slightly oval in outline and almost 2x longer than wide ( Fig. 19F ). Pedicellus very short, sub-spherical. III about equal in length to scapus, IV much shorter.

Thorax: Pronotum about equal in length and very slightly wider than head, somewhat narrowed pre-medially, about 1.2x longer than wide ( Fig. 19F ). Median line distinctly impressed over entire length of segment; the transverse median sulcus shallow, gently curved and expanding over entire width of segment. Anterior margin obtusely raised and with a median pair of blunt tubercles. Anterior portion with one or two pairs of conical tubercles just before transverse median sulcus; the posterior portion with four distinct tubercles, two small ones medially and two more widely spaced ones posteriorly. Meso- and metanotum with a very fine longitudinal median carina, both very sparsely set with indistinct, low granules dorsally and a row of 3–6 more prominent rounded, white tubercles laterally. Meso- and metapleurae each with a few rather small tubercles positioned in a longitudinal row. Mesosternum weakly, metasternum indistinctly tectinate longitudinally; each with only a very few very small paired granules. Mesothorax elongate and slender, almost cylindrical and about 2.1x longer than head and pronotum combined. Length of metanotum contained about 2.2x in that of mesonotum; about 2x longer than wide.

Abdomen: Median segment less than ½ the length of metanotum, just slightly wider than long and very slightly narrowed towards; surface with a fine longitudinal median carina and a widely spaced pair of small granules near posterior margin.Abdomen excluding median segment considerably longer head and complete thorax combined.All abdominal terga with a fine longitudinal median carina and smooth except for avery indefinite pair of widely spaced granules near posterior margin of II–V. Segments II–VII roughly of uniform width, slightly subequal in length and on average about 1.5x longer than wide. Sterna very weakly tectinate longitudinally and smooth. Sternum VII with Preopercular organ formed by a median pair of short, slightly digitiform lobes close to posterior margin ( Figs. 19C, E ). Tergum IX tectiform with a pair of small, obtuse posteromedian swellings. Anal segment about as long as IX, strongly tectiform with the lateral margins slightly deflexed into an obtusely dentiform lobe anteriorly ( Fig. 19D ); the posterior margin with a very wide and flat excavataion and the outer lateral angles acutely pointed and laterad directed. Epiproct large, obtusely triangular, shield-like and projecting notably beyond outer lateral apices of anal segment ( Fig. 19D ). Cerci small, obtusely conical and slightly compressed laterally ( Fig. 19C ). Subgenital plate strongly keeled, deeply convex and fairly bulgy post-medially ( Fig. 19C ); apex rounded and ± reaching to apex of abdomen ( Fig. 19E ).

Legs: All long, slender and entirely unarmed except for moderately prominent obtusely triangular and sometimes bi-dentate sub-apical lobe that is followed by a minute tooth on both ventral carinae of meso- and metafemora. Basitarsi slender and elongate, longer than following three tarsomeres combined.

♂ ( Figs. 19 B , 20C ). Medium to large (body length 68.0–83.0 mm), slender and elongate for the genus. Entire dorsal body surface with a very fine and flat, longitudinal median carina. General colour plain orange-brown, the legs with a reddish hue and very indistinctly annulated. Membranes between body segments slightly yellowish. Eyes dark yellow ( Fig. 20C ). Antennae much less distinctly annulated as in ♀♀. Cephalic tubercles yellow tipped.

Head: Generally as in ♀♀ but tubercles less numerous and less pronounced, the interocular pair of spines more acute and notably more prominent, and the eyes relatively larger with their diameter contained a little less than 2x in length of genae. Antennae longer than body; otherwise as in ♀♀.

Thorax: Pronotum generally as in ♀♀ but tubercles much less distinct. Mesothorax very elongate, slender and about 2.4x longer than head and prothorax combined, very slightly widened at anterior margin and somewhat widened posteriorly. Mesonotum almost smooth and just with single flat granules along lateral margins. Metanotum a little less than ½ the length of mesonotum and smooth. Meso- and metapleurae with a few very indistinct marginal granules. Sterna smooth and very weakly tectinate longitudinally.

Abdomen: Median segment a little less than ½ the length of metanotum, gradually narrowing towards the anterior and almost 2x longer than wide. Abdomen excluding median segment somewhat lonher than head and complete thorax combined; smooth. Segment II about 1.6x longer than median segment. II–VII uniform in width, II–V almost equal in length and VI–VII somewhat decreasing in length; II–V on average 3.5x longer than wide. Tergum VIII only 2/3 the length of VII and widening towards posterior, IX rectangular and slightly shorter; both keeled longitudinally. Anal segment strongly tectiform, the digitiform apical process slender straight, gradually narrowed towards a slender tip and about ¾ the length of broadened anterior portion of segment ( Fig. 19G ). Near lower lateral margin in anterior portion with a tuberculate longitudinal keel. Interior surfaces of digitiform processes irregularly set with differently sized black teeth ( Figs. 19H–J ). Cerci small, gently in-curving, laterally compressed in median portion with the interior surface concave; tip blunt ( Fig. 19J ). Poculum fairly small, roundly conical and reaching to posterior margin of tergum IX; with a fine longitudinal keel in posterior half and the posterior margin slightly labiate.

Legs: All long, slender and unarmed except for two sub-apical teeth on two outer ventral carinae of meso- and metafemora, the more apical one of which is considerably smaller. Basitarsi long, slender and about equal in length to remaining tarsomeres combined.

Nymphs: Newly hatched nymphs are bright mid green with yellow eyes and black legs that are irregularly spotted with white or pale grey. Abdominal terga XI and X with a black dorso-median marking. The colouration of later instars resemble those of adult ♀♀, but the legs are contrasting reddish brown with pale green to turquoise spots.

Egg ( Figs. 20D–E ): Small and typical for the genus, capsule barrel-shaped,> 1.6x longer than wide, notably higher than wide and oval cross-section with the posterior half somewhat narrowed. Capsule surface wholly but unevenly rugulose to coriaceous. Micropylar plate pear-shaped, notably longer than wide, approximately half the length of capsule with anterior portion gradually narrowing; outer margin weakly bulging and the inner portion with a slight medio-longitudinal bulge, which terminates towards posterior end of plate. Micropylar cup small and positioned in posteromedian gap of plate, median line short. Operculum oval, slightly convex and with a rim of low tubercles some distance off the outer margin. Capitulum irregularly shaped with about four deep lateral impressions and on a very short stalk. General colour of capsule greyish, slightly shiny and often with washed tones of yellow, red, blue and green; the lateral and ventral surfaces with a variable number of blackish markings. Micropylar plate yellowish ochre to straw, operculum dark grey and operculum dark reddish brown to almost black. Measurements [mm]: Overall length 3.2–3.4, length 2.9–3.1, width 2.0–2.1, height 1.6–1.7, length of micropylar plate 1.5–1.6.

Comments: Culture stock of this species was introduced by Daniel Dupont ( France) in 2006 and specimens were forwarded to the author for examination by Arnaud and Christophe Bauduin ( France) in 2008. The species has since been widely reared in captivity in Europe and feeds on various alternative food plants including bramble ( Rubus fruticosus , Rosaceae ), raspberry ( Rubus idaeus , Rosaceae ), hazel ( Corylus avellana , Betulaceae ) and ferns (Polypodiopsida). Eggs take about 3–4 months to hatch at average temperatures of 20–23°C. The nymphs are fairly slow-growing with ♂♂ taking 4.5–5 months and ♀♀ about 5–6 months to reach maturity. Females lay an average of two eggs per day, which are simply dropped to the ground. High humidity is necessary for all stages to ensure successful hatching of eggs and moulting.

Distribution: Apparently endemic to the Island of Peleng, the largest of the Banggai Islands positioned east of Sulawesi.

Figures

FIGURE 19. Myronides glaucus n. sp.: A. ♀ (PT), dorsolateral view [coll. FH, No. 0642-30]; B. ♂ (PT), dorsolateral view [coll. FH, No. 0642-12]; C. Lateral view of terminal abdominal segments of ♀ (PT) [coll. FH, No. 0642-30]; D. Dorsal view of terminal abdominal segments of ♀ (PT) [coll. FH, No. 0642-30]; E. Ventral view of terminal abdominal segments of ♀ (PT) [coll. FH, No. 0642-30]; F. Head and prothorax of ♀ (PT) seen dorso-laterally [coll. FH, No. 0642-20]; G. Lateral view of terminal abdominal segments of ♂ (PT) [coll. FH, No. 0642-32]; H. Dorsal view of terminal abdominal segments of ♂ (PT) [coll. FH, No. 0642-32]; J. Ventral view of terminal abdominal segments of ♂ (PT) [coll. FH, No. 0642-32]; K. Head and prothorax of ♂ (PT) in lateral view [NHMB].

FIGURE 20. Myronides glaucus n. sp.: A. Live captive reared ♀ (PT); B. Close up of head and thorax of live captive reared ♀ (PT); C. Close up of head and thorax of live captive reared ♀ (PT) in dorsal view; D. Egg (PT), dorsal view [coll. FH, No. 0642-E]; E. Egg (PT), lateral view [coll. FH, No. 0642-E].