Ramulus togianense, 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 : 80-84

Ramulus togianense n. sp.

( Figs. 32 , 33 , 35E–F )

HT, ♂: ex Zucht: F. Hennemann 2010–2014, Herkunft: O-Sulawesi, Prov. Sulawesi Tengah, Tomini Bucht, Togian-Inseln, Pulau Togean, leg. Bauduin [ ZSMC, ex coll. FH] .

PT, ♀, 3 eggs: ex Zucht: F. Hennemann 2010–2014, Herkunft: O-Sulawesi, Prov. Sulawesi Tengah, Tomini Bucht, Togian-In-seln, Pulau Togean, leg. Bauduin [ ZSMC, ex coll. FH] .

PT, 12 ♂♂, 21 ♀♀, 51 eggs: ex Zucht: F. Hennemann 2010–2014, Herkunft: O-Sulawesi, Prov. Sulawesi Tengah, Tomini Bucht, Togian-Inseln, Pulau Togean, leg. Bauduin [coll. FH, No’s 0733-1 to 33, E] .

PT, 37 ♂♂, 48 ♀♀: ex Zucht: O. Conle 2011, Herkunft: O-Sulawesi, Prov. Sulawesi Tengah, Tomini Bucht, Togian-Inseln, Pulau Togean, leg. Bauduin [coll. OC, No’s 0545-1 to 85] .

PT, 1 ♂, 8 ♀♀, 5 eggs: ex Zucht: O. Conle 2020, Herkunft: O-Sulawesi, Prov. Sulawesi Tengah, Tomini Bucht, Togian-Inseln, Pulau Togean, leg. Bauduin [coll. OC, No’s 0545-86 to 95] .

Etymology: The name refers to the distribution of this new species, which is an endemic of the Togian Islands in the Tomini Bay, east of Sulawesi.

Differentiatial diagnosis: Males of this new species are very similar to R. redemptus (Brunner v. Wattenwyl, 1907) but differ by the relatively shorter and somewhat more globose head ( Fig. 32J ), as well as the tapered and more distinctly protruded lower corners of the hemi-terga of the anal segment ( Fig. 32G ) and broadly rounded posterior margin of the poculum. Females are similar to those of R. globosicaput (Brunner v. Wattenwyl, 1907) and R. pelengense n. sp. but differ from both species by the very prominent, erect cephalic spines ( Fig. 32K ) and much more convex, boat-shaped subgenital plate ( Fig. 32D ). The eggs differ from those of both species by the comparatively less elongate and less slender shape (only 2.6x longer than high), the very indistinct and rounded dorsal projection of the operculum and the capsule having two posterolateral impressions ( Figs. 35E–F ).

Description: The colouration is described from photographs of live specimens ( Fig. 33 ).

♀ ( Figs. 32A–B ). Medium-sized (body length 123.5–142.0 mm), form moderately stocky for the genus with the body surface entirely smooth and slightly shiny, the head globose and with a very prominent pair of erect spines between the eyes. Colour mid to dull green, sometimes with a slight yellowish or greyish wash and body to a variable degree flecked with black (abdomen in particular and most distinct on abdominal tergum IV). Between the cephalic horn a more or less defined black transverse band. Pronotum with a faint block longitudinal median streak. Anal segment usually pale cream. Legs banded with black and basal portion of profemora pale cream. Antennae black apically, gradually becoming grey towards the base with pedicellus and scapus coloured like body.

Head: Strongly globose, broadest at the eyes, narrowed towards the posterior and with vertex moderately round-ed, convex and smooth. Between the eyes with a very prominent pair of erect and slightly laterad directed, laterally compressed horns, that are somewhat deflexed sub-basally and increasingly narrowed towards a pointed tip; projecting by at least 2/3 the height of head capsule ( Fig. 32K ). Between bases of antennae with a pair of shallow, transverse impressions. Eyes circular in outline, moderately projecting and their diameter contained 2.1x in length of genae. Antennae consisting of 21 antennomeres and about 1.6x longer than head and pronotum combined. Scapus compressed dorsoventrally with the lateral margin just moderately deflexed and very gently rounded; narrowing towards the base and about 3x longer than wide. Pedicellus less than 1/3 the length of scapus, cylindrical. III much longer than pedicellus, IV–XVI almost uniform in length the following gradually decreasing in length, only the two terminal ones considerably longer than preceding and terminal antennomere longest of all.

Thorax: Pronotum shorter and much narrower than head, widened medially with anterior margin a little narrower than posterior margin; slightly longer than wide. Transverse median sulcus prominent, curved with the outer ends strongly in-curving towards the anterior; just not reaching lateral margins of segment ( Fig. 32K ). Meso- and metanotum with a fine longitudinal median carina. Mesothorax 3x longer than combined length of head and prothorax and 1.3x longer than metanotum. Metanotum about 5x3x longer than wide.

Abdomen: Median segment very slightly wider than long, almost rectangular and its length contained more than 6x in that of metanotum. Abdomen excluding median segment notably longer than head and complete thorax combined. Segment II 2.8x longer than median segment. II–V slightly increasing, VI and VII decreasing in length, VII slightly longer than II; on average all about 2.5x longer than wide. Preopercular organ merely represented by a very indistinct swelling and a conspicuous black posteromedian marking on sternum VII ( Fig. 32F ). Tergum VIII about ¾ the length of VII and 2.25x longer than wide; IX of same width and 3/5 the length of VIII. Anal segment longer than IX, parallel-sided and with a longitudinal median carina, the posterior margin rectangular and with a small, triangular median incision ( Fig. 32E ). Epiproct small, triangular and just slightly projecting beyond posterior margin of anal segment ( Fig. 32E ). Cerci very small and gently in-curving. Subgenital plate boat-shaped, deeply keeled longitudinally with the lower margin rounded in lateral aspect and roughly reaching to tip of abdomen ( Fig. 32D ).

Legs: All long and slender with all carinae set with fine black setae. Posterodorsal carina of profemora with a few saw-like teeth, the other carinae unarmed. In meso- and metafemora the two dorsal carinae occasionally with 2–3 very minute, black teeth and the medioventral carina armed with a single, very blunt subapical tooth ( Fig. 32L ). Mesotibiae unarmed or with a triangular tooth of variable size some 1/3 off the base; if present on metatibiae this tooth is much smaller. Posterodorsal carina of metatibiae with a few small teeth in apical portion. Tarsi long and slender, probasitarsus 2x longer than combined length of remaining tarsomeres, meso- and metabasitarsus about 1.5x longer than remaining tarsomeres combined.

♂ ( Fig. 32C ). Moderately sized (body length 90.0–115.0 mm), slender and fairly typical for the genus with a globose head. Body chestnut brown, sometimes with a yellowish or orange wash. Head dark cream or ochre, eyes pale yellow. The prothorax, posterior portions of meso- and metathorax as well as anal segment mid to dull grey; apex of anal segment pale cream. Abdominal terga VIII and IX black ( Figs. 32G–H ). Legs reddish brown. Antennae blackish brown .

Head: Shape similar to that in ♀♀ but entirely unarmed ( Fig. 32J ). Two small and shallow impressions between bases of antennae. Eyes relatively larger and projecting hemispherically; their diameter contained only 1.7x in length of genae. Antennae slightly longer than head, pro- and mesothorax combined and consisting of 25 antennomeres; length relations generally as in ♀♀ but all antennomeres relatively much longer. Scapus compressed dorsoventrally and slightly narrowing towards the base and about 3x longer than wide; pedicellus cylindrical and a little less than ½ the length of scapus.

Thorax: Pronotum shorter and narrower than head ( Fig. 32J ); shape generally as in ♀♀ with the median portion broadened and lateral margins convex in dorsal aspect. Mesothorax very elongate and slender, about 3.3x longer than head and pronotum combined and almost 1.4x longer than metanotum.

Abdomen: Median segment 1.2x longer than wide and very slightly narrowing towards the anterior and its length contained about 6.75x in that of metanotum. Abdomen excluding median segment notably longer than head and complete thorax combined. Segment II 3x longer than median segment, and equal in length to III–V; these on average 5.3x longer than wide. VI–VII noticeably decreasing in length with VII only 2/3 the length of II. All of uniform width. Tergum VIII widening towards the posterior and a little more than ½ the length of VII, IX slightly shorter and widest of all segments with the lateral margins gently deflexed and rounded. Anal segment longer and higher than the two preceding terga, very strongly tectiform and split; the hemi-tergites broad and almost rectangular in basic shape with only the lower apical corner protuded into a short and blunt process ( Fig. 32G ); interior surfaces armed with several minute denticles ( Fig. 32H ). Cerci short, moderately slender and gently in-curving. Poculum fairly small, moderately scoop-shaped and with the posterior margin labiate; roughly reaching to posterior margin of abdominal tergum IX ( Fig. 32G ).

Legs: All very long and slender; unarmed except for a very indistinct, obtuse sub-apical tubercle on medioventral carina of meso- and metafemora and a few minute teeth in apical portion of posterodorsal carina of metatibiae. Basitarsi very long and very lender, probasitarsus 2.5x longer than combined length of remaining tarsomeres, meso-and metabasitarsus almost 2x longer than remaining tarsomeres combined.

Nymphs: Newly hatched nymphs are white and all over furnished with greyish green markings, that are encircled by a fine black line. The two terminal abdominal segments are black and the legs are irregularly banded with white and black. In later instars these colours gradually turn to yellow and green tones but the white or pale cream portions are retained until penultimate instar.

Variability: Females show variability in colouration, armature of the mesotibiae and also slight variation is seen in the size and shape of the cephalic horns. No noteworthy variability is observable in ♂♂.

Eggs ( Figs. 32E–F ): Medium-sized, moderately elongate and only about 2.7x longer than high, strongly flattened laterally almost 1.8x higher than wide; lateral surfaces roughly parallel-sided. Capsule in lateral aspect with the anterior one third somewhat narrowed and very slightly bent towards the ventral side. Entire capsule surface weakly uneven, very densely and minutely granulose and all over irregularly covered with small, peg-like tubercles. The polar area with a very wide, obtusely angular indention and the dorsal surface distinctly impressed at the micropylar plate. Dorsal and ventral surfaces each with a very obtusely rounded medio-longitudinal bulge, on both sides bordered by a longitudinal row of irregular, differently sized but deep impressions; the dorsal bulge interrupted at micropylar plate. Lateral surfaces flat with a few small impressions, usually two more distinct impression in anterior one third and with two very prominent, large and irregularly shaped impressions close to polar area. Micropylar plate fairly large, bilobed and consisting of two roughly oval sections the laterally expand almost half way over lateral surfaces of capsule; the outer margin very narrow and impressed. Micropylar cup a cup-like structure that is positioned in the posteromedian gap of micropylar plate. Operculum oval with the outer margin raised and forming an obtusely crenulate rim that is highest dorsally. Average measurements [mm]: Length (including operculum) 6.5, length 6.1, width 1.3, height 2.3, length of micropylar plate 1.5.

Comments: Culture stock of this species is believed to have been first introduced into Europe in 2006 and is since successfully reared in captivity. It is fairly easy to rear in spacious cages and accepts numerous alternative food plants, that include bramble ( Rubus fruticosus , Rosaceae ), raspberry ( Rubus idaeus , Rosaceae ), roses ( Rosa spp. , Rosaceae ), hazel ( Corylus avellana , Betulaceae ) and oak ( Quercus robur , Fagaceae ). Females produce about three eggs per day and simply flick these away by an abrupt movement of the abdomen. At average temperatures of 22–25°C eggs hatch after 5–6 months with hatching rates usually above 70% when humidity is kept high.

Distribution: Only know from the type-locality, Pulau Togean one of the Togian Islands in the Gulf of Tomini, East Sulawesi.

Figures

FIGURE 32. Ramulus togianense n. sp.: A. ♀ (PT), dorso-lateral view [coll. FH, No. 0733-4]; B. ♀ (PT), dorso-lateral view [coll. FH, No. 0733-]; C. ♂ (HT), dorso-lateral view [ZSMC]; D. Lateral view of terminal abdominal segments of ♀ (PT) [coll. FH, No. 0733-31]; E. Dorsal view of terminal abdominal segments of ♀ (PT) [coll. FH, No. 0733-31]; F. Ventral view of terminal abdominal segments of ♀ (PT) [coll. FH, No. 0733-31]; G. Lateral view of terminal abdominal segments of ♂ (HT) [ZSMC]; H. Dorsal view of terminal abdominal segments of ♂ (HT) [ZSMC]; J. Head and prothorax of ♀ (HT) seen dorsolaterally [ZSMC]; K. Head and prothorax of ♀ (PT) seen dorso-laterally [coll. FH, No. 0733-30]; L. Apex of right mesofemur of ♀ (PT) seen intero-laterally [coll. FH, No. 0733-6].

FIGURE 33. Ramulus togianense n. sp., live insects: A. ♀ (inset: head and prothorax); B. Close up of head, pro- and mesothorax of ♂; C. ♂.

FIGURE 35. Ramulus spp., eggs: A. R. globosicaput (Brunner v. Wattenwyl, 1907), dorsal view [coll. FH, No. 0303-E]; B. R. globosicaput (Brunner v. Wattenwyl, 1907), lateral view [coll. FH, No. 0303-E]; C. R. torajanus n. sp., dorsal view (PT) [coll. FH, No. 1064-E]; D. R. torajanus n. sp., lateral view (PT) [coll. FH, No. 1064-E]; E. R. togianense n. sp., dorsal view (PT) [coll. FH, No. 0733-E]; F. R. togianense n. sp., lateral view (PT) [coll. FH, No. 0733-E]; G. R. pelengense n. sp., dorsal view (PT) [coll. FH, No. 0790-E]; H. R. pelengense n. sp., lateral view (PT) [coll. FH, No. 0790-E];