Tisamenus clotho ( Rehn & Rehn, 1939 )

Hennemann, Frank H., 2025, A taxonomic review of Philippine Obrimini stick insects: The genus Tisamenus Stål, 1875 (Insecta: Phasmatodea: Heteropterygidae: Obriminae), Faunitaxys 13 (24), pp. 1-85 : 24-28

Tisamenus clotho ( Rehn & Rehn, 1939)

( Fig. 11-13, 46 G-H)

Hoploclonia clotho Rehn & Rehn, 1939: 473 , pl. 34: 29 (♀).

HT, ♀: Polillo Taylor ; Hoploclonia clotho Rehn&Rehn Type H. 1345; Data Base Serial No. Assigned as Type No. September 2008. Type # 9125 [ANSP];

PT, ♀: Polillo Taylor ; Hoploclonia clotho Rehn & Rehn, Allotype Paratype; Allotype No. 53316 U.S. N.M. [USNM];

PT, ♀ (juveniles): Polillo Taylor ; 16748; Hoploclonia clotho Rehn & Rehn , Paratype [USNM];

PT, 2 ♀ (juveniles): PolilloTaylor; 16748; Hoploclonia clotho Rehn & Rehn , Paratype [ ANSP] ;

PT, ♂ (juvenile): Polillo Taylor ;

Hoploclonia clotho Rehn & Rehn , Paratype [ANSP].

Tisamenus clotho, Zompro, 2004: 206 .

- Otte & Brock, 2005: 334.

- Brock & Büscher, 2022: 521.

- Hennemann, 2023b: 128.

= Hoploclonia atropos Rehn & Rehn, 1939: 475 , pl. 35: 36 (♀). HT, ♀: Philippine Ids. 1932 ; E H Hareford Coll;

Hoploclonia atropos Rehn & Rehn , Type; Type No. 53315 U.S. N.M. [USNM]. n. syn.

Tisamenus atropos, Zompro, 2004: 206 .

- Otte & Brock, 2005: 334.

- Brock & Büscher, 2022: 521.

- Hennemann, 2023b: 128.

Material examined

6 ♀, 5 ♂, 13 eggs:ex Zucht F.Hennemann 2020, Herkunft: Philippinen. SLuzon, BicolReg., Prov. Camarines Norte, Bagacay & Mananap [ FH, No’s 1039-1 to 11 & E] ;

1 ♂, 1 ♀ (penultimate instar): Philippinen, Zentral Luzon Id., Provinz Nueva Ecija, Gabaldon, local collector VIII.2012 [ FH, No’s 1029-12 & 13] .

Differentiation. – This distinctive species is characteristic for combining a stocky shape and strongly widened meso- and metapleurae with a prominent head and body armature. Morphologically it is most similar to T. hystrix ( Rehn & Rehn, 1939) and T. lachesis ( Rehn & Rehn, 1939) . From hystrix , which is an endemic of the island of Sibuyan and thus geographically separated, ♀ are distinguished by the slightly larger dimensions and heavier built with stockier and less elongate legs, the metatibiae of which do not reach the apex of the ovipositor ( Fig. 11 A-E). There is a prominent pair of posteriors on abdominal terga II-V (often also on VI-VII in hystrix ) and a small posterior mesal on all abdominal terga and the pair of inter-posterior tubercles on the meso- and metanotum seen in hystrix , are missing in clotho ( Fig. 11C, I). Males are easily separated from those of hystrix by the stockier body shape and limbs ( Fig. 12 A- D) and notably more incrassate metafemora ( Fig.12E), which possess a distinct ventro-basal swelling, the lack of inter-posterior meso- and metanotals and posteriors on abdominal terga V-VI (occasionally very small on V; Fig. 12C). From the notably larger lachesis both sexes of clotho are readily distinguishable by the much stockier overall shape and relatively shorter body segments, more widened meso- and metapleurae and longer pleural spines, as well as the wider mesonotal triangular area, which is about as long as it is wide across the anterolateral angles and roughly forms an isosceles triangle (distinctly longer than wide in lachesis ). The eggs ( Fig. 46 G-H) may be distinguished from those of lachesis by the bulgier shape, lighter greyish colour, much less developed fringy carinae and hairy structures of the capsule, fairly wide anterior constriction just below the anterior margin of the capsule and notably longer posterolateral extensions of the micropylar plate. From the eggs of hystrix they can be distinguished by the broadly constricted anterior margin and slightly less developed sculpturing of the capsule as well as the somewhat longer posterolateral extensions of the micropylar plate.

Description ♂ ( Fig. 12)

Form and colouration. – Size average for the genus (body length 37.0- 42.5 mm); general form rather stocky, legs fairly strong and slightly incrassate; elements of armature rather prominent with strong meso- and metapleural spines. General colour mid brown with most spines tipped with grey ( Fig. 13C), the meso- and metasternum tawny and the femora with faint tawny markings ventrally ( Fig. 12D). Antennae drab with the terminal twelve joints buff.

Head. – Sub-quadrate, scarcely longer than wide with the genae roughly parallel-sided.The three supra-orbitals moderatelyprominent, conical with the median one largest ( Fig. 12J);occipitals and median coronals rather small, and much lower than orbitals, the lateral coronals tuberculate, weakly bifid and somewhat larger than occipitals. Eyes fairly large, hemispherical and their diameter corresponding to about 0.6x length of gena. Genae supplied with 2-3 low,tuberculate gulars.Antennae strong,perlamorph with all joints fairly short and consisting of 24 joints ( Fig. 12J); scapus triangular in dorsal aspect, A. Dorsalview [ FH 1039-6 ]. B. Dorsolateralview [ FH 1039-6 ]. C. Lateralview [ FH 1039-6 ]. D. Ventral view [ FH 1039-6 ]. E. Holotype, dorsal view [ ANSP]. F. Terminalia in lateral view [ FH 1039-6 ]. G. Terminalia in dorsalview[ FH 1039-6 ]. H. Terminalia inventralview [ FH1039-6 ]. I. Closeup of head, pro- and mesonotum [ FH 1039-6 ]. J. Closeup of pro-, meso- and metasternum [ FH 1039-6 ].

A. Dorsal view. B. Dorsolateral view. C. Lateral view. D. Ventral view. E. Anteroventral view of left hind leg. F. Terminalia in lateral view. G. Terminalia in dorsal view. H. Terminalia in ventral view. I. Closeup of head, pro- and mesonotum [FH 1039-6]. J. Closeup of pro-, meso- and metasternum.

pedicellus about half the length of scapus and almost cylindrical; III slightly longer than pedicellus, IV much shorter and up to XII slightly increasing in length, then very weakly decreasing with the terminal antennomere much elongated and slightly longer than preceding two joints combined.

Thorax. – Pronotum sub-quadrate; triangular area just weakly indicated with margins behind the transverse median sulcus bounded by sub-obsolete granules and anterolaterally with a strong bifid spine, whose second spike is somewhat longer than the anterior one ( Fig. 12C, J). Mesothorax broad, widening towards the posterior but with outer margins of mesopleurae gently convex in outline ( Fig. 12A); about 2.2x longer than prothorax and with posterior portion 1.6x wider than anterior margin. Mesonotum sub-trapeziform with lateral margins very slightly convergent towards the posterior and with a narrowing post-medially, about 2.2x longer than width at anterior margin; the triangular area almost attaining middle of notum, about as long than wide, disk shallowly concave and the margins shallowly granulate with the anterolateralanglesprotruded intoanobtusely rounded tubercle ( Fig.12J); posterior portion of mesonotum with a broadand shallowly granulate medio-longitudinal bulge, that is faintly indicated in the triangular area; the posterior portion of the bulge weakly raised and rounded ( Fig. 12C, J). Mesopleurae notably expanding towards the posterior and convex in outline with four laterals, the antero-lateral small and sub-obsolete, the second notably larger and the third and fourth prominent, spinose; mesopleural a prominent conical spine. Metanotum trapezoidal with a post-anterior narrowing, a little longer than wide and with the same granulose medio-longitudinal keel seen on mesonotum; which is somewhat gibbose posteriorly if seen sideways. Metapleurae with two laterals, the anterior one of which is small and sub-obsolete and the second strong and tubercular; metapleural small, tubercular A. ♀ near Mount Isarog, Camarines Sur, South Luzon [© Albert Kang https://inaturalist.ca/observations/57639420]. B. Captive reared ♀ from Camarines Norte Province, South Luzon. C. Captive reared ♂ from Camarines Norte Province, South Luzon.

and the supra-coxal angle with a strong supra-coxal spine. Mesosternum distinctlytri-carinate with the lateral carinae supplied withthree shallownodelike mesosternals; anteriorly the lateral carinae are connected by a distinct, straight transverse carina Fig. 12I); metasternum with a shallow medio-longitudinal carina and a few faint indications of metasternals laterally.

Abdomen. – Median segment transverse with anterior margin broadly rounded, shallowly carinate medio-longitudinally and with a very small nodose pair of second paired posteriors. Segments II-VI very slightly decreasing in width and somewhat sub-uniform in length with III-V roughly quadrate but II and VII weakly transverse and II trapezoidal in outline; terga II andIII withlow tuberculate pairedsecond posteriors (just representedassmall nodes on IV). Terga II-VII with very faintly indicated medio-longitudinal carina, which is more pronounced but rather obtuse on VIII and IX and posteriorly terminates in a low node on these two terga. Sterna II-VII with a fine medio-longitudinal carina ( Fig. 12D). Anal segment longer than IX, somewhat cucullate in lateralaspect ( Fig. 12F), narrowed posteriorly with the lateral margins shallowly angular and the dorsal surface with an obtuse and low medio-longitudinal bulge; posterior margin with a broad and very shallow, concave median excavation and the outer angles protruded and shortly digitiform ( Fig. 12G). Epiproct distinct, shield-shaped and almost semi-circular in shape and notably projecting beyond anal segment ( Fig. 12G). Vomer very broad, distinctly transverse with a short but strong, upcurved terminal hook. Poculum rounded, cucullate with a large and very broad, weakly labiate posterior flange ( Fig. 12H), that is slightly down-curved and reaches more than halfway along anal segment ( Fig. 12F).

Legs. – All stocky with the femora somewhat incrassate; the femoral teeth however comparatively small. Pro- and mesofemora somewhat shorter than mesothorax, metafemora reaching halfway along abdominal segment V and metatibiae roughly reaching to tip of abdomen. Ventro-basal swelling of metafemora distinct, sub-globose and supplied with two small, rounded tubercles ( Fig. 12E); the four teeth of dorsal carinae increasing in size towards base of femur with the two basal teeth prominent and somewhat spiniform. Metatibiae smooth dorsally and with 5-10 small, blunt teeth-like swellings ventrally ( Fig. 12E). Basitarsi short and just slightly longer than following two tarsomeres taken together.

Measurements [mm]. – Body 37.0-42.5, pronotum 3.2-3.6, mesonotum 7.0-7.7, metanotum 3.1-3.9, median segment 2.0-2.3, profemora 7.0-7.3, mesofemora 5.1-5.4, metafemora 7.7-8.1, protibiae 6.8-7.0, mesotibiae 5.7-6.1, metatibiae 8.1-8.6, antennae 12.5-13.5.

Egg ( Fig. 46 G-H)

Large for the genus; capsule oval with the anterior portion possessing a distinct constriction just below anterior margin and the dorsal surface slightly bulgier than ventral surface; oval in cross-section and notably higher than wide; the capsule 1.6x longer than wide. Surface very minutely but densely granular andwith a rather shallow, unevenandnot fully contiguous meshwork of fine ridges;these most pronounced antero-dorsally andat polar-area where these ridges are partly covered by short, fringy to setose structures. Micropylar plate fairly large and almost 0.8x the length capsule; broadly Y-shaped with the median portion large but not reaching anterior margin of capsule and the two posterolateral extensions moderately sized, somewhat narrowed apically and directed about 40° off the axis of the egg capsule; the posterior portion rather narrowly V-shaped with a small bowl-shaped micropylar cup in centre. Outer margin of plate marked by an unevenly granular but rather narrow bulge; the interior surface notably inflated and densely bur unevenly rugulose to tubercular; a rather broad rim between the outer margin and raised inner portion somewhat indented and lacking and protrusions. Median line marked by a shallow and rather short fringy bulge that scarcely extends to the lower margin of the posterolateral extensions of the micropylar plate. Operculum oval and just very weakly convex in centre; surface with several irregular radially directed carinae and rugulae the interiorly merge to form an uneven raised rim of rugulae; outer margin somewhat inflated and granular. Colour uniformly mid grey with the fringy appendages of the capsule yellowish ochre; outer margin of micropylar plate brown. Measurements [mm]: Length incl. operculum 4.2, length 4.1, width 2.5, height 3.0, length of micropylar plate 3.2.

Variability. – Slight variability is seen in the size of the cephalic, thoracic and abdominal armature, the holotype of H. atropos Rehn & Rehn, 1939 , for example, having all the spines, but the pronotal anteriors and second paired posteriors of the basal abdominal terga in particular notably less developed than in all the other specimens at hand. Noteworthy variability is seen in the mesopleural laterals of ♀, which vary in that the two anterior spines range from very small and sub-obsolete to tubercular and occasionally some ♀ possess an additional small spinose lateral in the anterior portion making a total of five instead of the usual four laterals (e. g. sample coll. FH, No. 1039-5). Body length of ♀ 49.0-57.0 mm.

Remarks. – Rehn & Rehn (1939: 473) described Hoploclonia clotho from a series of ♀ examples from the island of Polillo. Examination of the ♀ from an unspecified locality and representing the holotype of H. atropos Rehn & Rehn, 1939 in the collection of USNM and comparison with clotho leaves no doubt it is a specimen with slightly less pronounced elements of armature of the same species. Thus, atropos is here synonymised under clotho because the latter species has page preference (n. syn.). The only two characters that Rehn & Rehn consulted to separate atropos from clotho are the straight instead of arcuate converging carinae of the mesonotal triangular area and slightly shorter and proportionally heavier legs. Both characters however lie within the range of intraspecific variability as can be seen by the examination of more comprehensive material now available for examination (see above). Moreover, other species in the genus like T. lachesis ( Rehn & Rehn, 1939) have shown Polillo not necessarily to harbour endemic species but several species to be also found on Luzon. The ♂ and egg are here formally described for the first time and illustrated.

Specimens were found in the Camarines Norte province by Thierry Heitzmann ( Philippines) on two occasions and at two different localities in 2015, this is Mount Bagacay and Mananap Falls. Eggs were sent to Europe for breeding purposes and a culture could be established, which has however not been given a culture number by the Phasmid Study Group. It was identified by Joachim Bresseel (RBINS) and was first distributed as Tisamenus cf. clotho ‘Camarines’ and later as T. clotho .

Distribution. – Polillo Island [ANSP, USNM – type locality]. SLuzon. Bicol Region: Province Camarines Norte (Mananap Falls [FH]; Bagacay [FH]); Province Camarines Sur (Bula [photographic record by Albert Kang: https://inaturalist.ca/ observations/57639420]. C-Luzon: Province Nueva Ecija (Gabaldon [FH])