Tisamenus charestae Hennemann & Le Tirant, 2025

Tisamenus charestae Hennemann & Le Tirant View in CoL n. sp.

( Fig. 9 - 10, 46E - F)

ZooBank: https://zoobank.org/ 787B4F6A-9983-4102-ADC1-E39874880FC4

HT, ♀: Philippines, N Luzon Id., Province Ifugao, Central Cordillera , Cambulo trail, 1750 m, local collector 24.III.2021 [ IMQC] .

PT, 2 ♀, 1 ♂: Philippines, N Luzon Id., Province Ifugao, Central Cordillera , Cambulo trail, 1750 m, local collector 24.III.2021 [ IMQC] .

PT, 7 ♀, 2 ♂, 1 egg (ex ovipositor): Philippinen, N Luzon Id., Provinz Ifugao, Central Cordillera , Cambulo trail, 1750 m, local collector 24.III. 2021 [ FH, No’s 1355-1 to 9 & E] .

PT, 1 ♀, 1 ♂: Coll. R.I.Sc.N.B., Philippines, N Luzon Id., Provinz Ifugao, Central Cordillera , Cambulo trail, 1750 m, local collector 24.III.2021 [ RBINS] .

PT, 1 ♀, 1 ♂: Ifugao, Philippines, leg. Heitzmann 2014 [TB] .

Differentiation. – Both sexes are morphologically closest to T. polillo ( Rehn & Rehn, 1939) but may be separated by the smaller size, slightly stockier overall shape and limbs ( Fig. 9A–D, 10 A-D). Males may also be differentiated by stronger and less pointed supra-coxals of the meso- and metapleurae, having the anterior pronotals represented by two large just slightly unequally sized spines ( Fig. 10F; tri-spinose in polillo with the spines notably decreasing in size towards the A. Dorsal view [FH 1355-2]. B. Dorsolateral view [FH 1355-2]. C. Lateral view [FH 1355-2]. D. Ventral view [FH 1355-2]. E. Closeup of head,pro- and mesonotum [FH 1355-1]. K. Closeupof pro-,meso- andmetasternum [FH 1355-2]. G. Terminalia in lateralview. H. Terminalia in dorsal view. I. Terminalia in ventral view.

posterior), having the armature of the limbs comparatively more pronounced and the smaller epiproct ( Fig. 10H). Females of this new species are moreover distinguishable from those of polillo by the much shorter, conical and rather tubercular than spinose supra-coxals of the meso- and metapleurae, notably smaller sub-obsolete mesopleurals (more or less spinose in polillo ), smaller dentations of the outer margins of the mesonotal triangular area ( Fig. 9E), having the paired posteriors of the abdominal terga II-IV merely represented as small tubercles (distinct spines in polillo ), as well as the longer subgenital plate that extends beyond the epiproct by more than half of whose length. Due to the reduced body armature ♀ also show similarity affinity to those of the Luzonian T.asper Bolivar, 1890 and T. cervicornis Bolívar, 1890 but differ from both species by the smaller size, much slenderer general shape and more elongate limbs ( Fig. 9 A-D). From the first they differ by the smaller laterals of the meso- and metapleurae, which are only represented by obtuse tubercles (small spines in asper ), more spinose cephalic and prothoracic armature ( Fig. 9E), more distinctly raised carinae of the mesonotal triangular area ( Fig. 9E) and the longer subgenital plate, which projects notably beyond the epiproct ( Fig. 9 G-H). From cervicornis they are easily separable by the larger mesonotal triangular area which attains the middle of the mesonotum ( Fig. 9E), less acute and comparatively smaller supra-coxals of the meso- and metapleurae, lack of the paired posterior spines of abdominal terga I-IV and longer antennae, which project beyond the tip of the protibiae. The eggs are characteristic for the small micropylar plate, which has all three extensionsrather short and correspondsto only abouttwo-thirds of the capsule length ( Fig. 46E).

Etymology. – This small new species is named after Sonya Charest, the head of education of the Montréal Insectarium (IMQC) for over 30 years and long-term colleague and friend of the second author. She was also involved in the Monarch Watch programme and this species is named after her to honour her enormous efforts for entomological education and various other projects at the Montréal Insectarium, the largest insect museum in Canada.

Description ♀ ( Fig. 9)

Form and colouration. – Size small (body length 38.0-43.0 mm), general form slender and elongate, the elements of armature rather weakly developed and the legs slender and elongate. Body surface unevenly granular. General colour mid to dark brown or almost black, often with a slight orangey to reddish washin lighter specimens; most of the larger elements of armature blackish and the medio-longitudinal keel of the thorax and mesonotal triangular area russet. Sterna somewhat lighter in colour. Antennae with two basal segments coloured like body, the following reddish mid brown and the 4-5 terminal joints rather ochraceous.

Head. – Sub-quadrate and scarcely longer than wide with the genae parallel-sided and the vertex gently convex medio-posteriorly. Supra-orbitals represented by twomoderately prominent elongate tubercles, the anterior one of which is notably larger than the second ( Fig. 9E); occipitals much lower and tuberculate; the four occipitals somewhat more pronounced than occipitals and bifid with the lateral coronals larger than medials. Surface otherwise irregularly tuberculate and genae with about three low, tubercular gulars. Eyes small, hemispherical and their diameter corresponding to slightly less than half the length of gena.Antennae not reaching to tip of front legs and consistingof 26joints;scapus about2x longer thanwide andtapering towards base, pedicellus cylindrical and less than half as long, III about as long as pedicellus andthe following antennomeres first increasingand towards the tip of antennae decreasing in length; terminal antennomere much elongated and about as long as scapus.

Thorax. – Pronotum sub-trapeziform, somewhat wider than head; the triangular area faintly indicated by two converging rows of tubercles that gradually decrease in size towards the posterior; the anteriors represented by fairly prominent but obtuse bifid spines ( Fig 9E). Transverse sulcus distinctly indented. Mesothorax 2.45x longer than prothorax and slightly gradually widening towards posterior. Mesonotum roughly rectangular and about 1.7x longer than wide; triangular area slightly surpassing middle of notum, length slightly more than width across anterolateral angles, the margins weakly convex and obtusely tubercular, the anterolateral angle rounded tuberculate; the interior surface concave ( Fig. 9E). Posterior portion of mesonotum with a distinct granular medio-longitudinal keel that is faintly indicated in the triangular area; lateral margins unevenly granular. Mesopleurae slightly widening towards posterior with five very low, sub-obsolete tubercular laterals; the laterally migrated, conical mesopleural notably larger than laterals. Metanotum notably wider than long, trapezoidal in outline and with the same granular medio-longitudinal keel seen on mesonotum; the posterior with a pair of somewhat enlarged tuberculiform granules. Metapleurae with three small, sub-obsolete tubercular laterals and a fairly small tubercular metapleural; the supra-coxal angle moderately protruded and with a relatively small, conical supra-coxal. Mesosternum weakly carinate medio-longitudinally and destitute of mesosternals ( Fig. 9F). Metasternum only with a faintly indicated medio-longitudinal carina.

Abdomen. – Segments I-VIII broadly transverse; median segment with anterior margin broadly rounded and weakly tectiform medio-longitudinally, following terga with a slight trace of a medio-longitudinal carina; II-V about 2.6 wider than long; V-X gradually narrowing; VII trapezoidal in dorsal aspect, only two-thirds the width of III-V. Terga II-IV with second paired posteriors merely represented by very low granular swellings. Sterna II-VII destitute of any noteworthy armature; praeopercular organ formed by a somewhat raised posterior margin in the median portion, that bears a small tubercular swelling at each lateral end. Tergum IX obtusely tectate and with a moderate, tubercular posteromedian swelling ( Fig. 9G). Anal segment strongly declining with the lateral margins obliquely convergent in posterior half and with a fairly well developed medio-longitudinal carina; close to anterior margin with a closely spaced pair of nodes and posterior margin broadly rounded ( Fig. 9H). Epiproct weakly tectate longitudinally with an indication of a medio-longitudinal carina, the lateral margins weakly and obliquely convergent and the posterior margin rounded with a small median protrusion. Subgenital plate fairly elongate, notably projecting beyond epiproct, navicular, distinctly carinate in posterior half and the apex narrowly triangular and acute ( Fig. 9 G-I).

Legs. – All slender and elongate with the teeth much reduced; all carinae of metatibiae only with about three obtusely dentiform swellings. Pro- and mesofemora somewhat shorter than mesothorax; metafemora reaching about halfway along abdominal segment V and metatibiae roughly reaching to tip of abdomen. Basitarsi about as long as following three tarsomeres taken together.

Measurementsof holotype [mm]. – Body 39.7, pronotum 3.1, mesonotum 7.1, metanotum 3.0, median segment 1.9, profemora 7.3, mesofemora 5.7, metafemora 9.8, protibiae 7.6, mesotibiae 6.5, metatibiae 9.8, antennae 12.7.

Measurements of paratypes [mm]. – Body 38.0-43.0, pronotum 2.9-3.2, mesonotum 6.8-7.2, metanotum 2.9-3.1, median segment 1.8-1.9, profemora 6.8-7.4, mesofemora 5.6-5.8, metafemora 8.8-9.6, protibiae 7.2-7.5, mesotibiae 6.2-6.9, metatibiae 9.0-10.0, antennae 12.7-13.3.

♂ ( Fig. 10)

Form and colouration. – Size small (body length 29.6-30.7 mm), general form fairly slender and elongate, the elements of armature essentially like in ♀ but comparatively more developed; the legs broader and stouter with the metafemora moderately incrassate and thickened towards the base. Colour like in ♀. The terminal twelve antennomeres ochraceous and lighter in colour than rest of antennae.

Head. – Like in ♀ but the anterior supra-orbital much longer and spinose ( Fig. 10F) and the eyes proportionately somewhat larger with their diameter corresponding to only about 0.6x the length of gena. Antennae only with 24 segments with all joins proportionally shorter; almost reaching to tip of protarsi.

Thorax. – Pronotum essentially as in ♀ but less trapeziform in outline and the bifid anterior much longer, spinose with the anterior spine projecting over anterior margin of notum ( Fig. 10F). Mesothorax 2.3x longer than prothorax and just slightly widening towards posterior. Mesonotum sub-trapezoidal with the lateral margins slightly converging towards the posterior and about 2.1x longer than width at anterior margin; the triangular area notably longer than in ♀ being about 0.7x the length of mesonotum and 1.6x longer than width across anterolateral angles; the lateral margins weakly concave and the anterolateral angles sub-spiniform ( Fig. 10F); posterior portion with a distinct medio-longitudinal bulge that bears two parallel rows of granules, the bulge not notably continued in the concave interior region of the triangular area. Mesopleurae weakly widening towards the posterior with the mesopleural represented by a fairly prominent, slightly backward arched spine. Metanotum trapezoidal in outline, noticeably longer than wide and with the same medio-longitudinal bulge seen in back of mesonotum; a closely spaced pair of nodes pre-posteriorly. Metapleurae with three nodulose laterals and a weakly enlarged; the supra-coxal angle moderately protruded and with a fairly prominent supra-coxal spine, that is slightly smaller than the mesopleural. Mesosternum densely granular and obtusely tri-carinate, the lateral carinae more granular ( Fig. 10G). Metasternum with a distinct medio-longitudinal keel and lateral carinae indicated by uneven granules.

Abdomen. – Median segment distinctly trapezoidal in outline with the anterior margin rounded and the anterolateral areas somewhat impressed. Segments II-VII almost uniform in length and width, II sub-trapeziform and III-VII sub-quadrate; the second paired posteriors merely represented by weakly enlarged nodes. An indicated medio-longitudinal carina only on sterna II-IV. Terga VIII and IX somewhat transverse and with an obtuse medio-longitudinal ridge, which on IX is posteriorly protruded into a fairly distinct conical swelling; the posterolateral angles of IX. Anal segment distinctly trapezoidal, somewhat declining towards the posterior, the lateral margins angular and the posterior margin concave with the outer angles obtusely protruded ( Fig. 10H). Epiproct broadly transverse and weakly rounded ( Fig. 10H). Vomer shorter than width at base, the basal portion A. Dorsal view. B. Dorsolateral view. C. Lateral view. D. Ventral view. E. Live couple from Ifugao, Luzon (© Rob Krijns). F. Closeup of head, pro- and mesonotum. G. Closeup of pro-, meso- and metasternum. H.Terminalia in dorsal view. I. Terminalia in ventral view.

indented medially and the outer margin somewhat convex and inflated and the terminal hook short and somewhat displaced towards the right. Poculum rather shallowly cup-shaped with the posterior flange very broad, weakly bi-labiate and emarginate medially ( Fig. 10I).

Legs. – All teeth comparatively more developed than in ♀. Pro- and mesofemora shorter than mesothorax, metafemora reaching about one-third the way along abdominal segment VI and metatibiae projecting beyond tip of abdomen by roughly the length of anal segment. Ventral teeth more spiniform than those on dorsal carinae. Ventro-basal portion of metafemora weakly gibbose and the two outer ventral carinae armed with 4-5 fairly distinct spiniform teeth; the ventral carinae of metatibiae each with about 3-4 obtuse teeth. Tarsi like in ♀.

Measurements of paratypes [mm]. – Body 29.6-30.7, pronotum 2.4-2.5, mesonotum 5.3-5.6, metanotum 2.7-2.8, median segment 1.7, profemora 5.6-5.8, mesofemora 4.8-5.0, metafemora 7.1-7.3, protibiae 5.6-5.9, mesotibiae 4.8-4.9, metatibiae 6.1-6.5, antennae 9.7-10.0.

Egg ( Fig. 46E–F)

Small for the genus; capsule ovoid but widest about one-third below anterior margin, the dorsal surface just scarcely more convex than ventral surface and the polar-area with a shallow indention; slightly oval in cross-section, notably higher than wide and capsule 1.6x longer than wide. Surface densely but unevenly covered by node-like to tubercular protuberances; these notably fewer in number just below the weakly inflated and granular anterior margin. Micropylar plate small and only about 0.67x the length capsule; Y-shaped with the median portion large and rather broad but staying clearly away from anterior margin of the capsule and the two posterolateral extensions small, narrowing and directed about 35° off the axis of the egg capsule; the posterior portion narrowly V-shaped with a very small tubercular micropylar cup in centre. Outer margin of plate marked by a granular bulge; the surface essentially sculptured like capsule but with the protuberances distinctly fewer to almost wanting along the outer margin. Median line a distinct but shallow longitudinal bulge that slightly projects below the posterolateral extension of the plate. Operculum oval with the central portion notably raised but flat and with a shallow indention in centre; outer opercular collar and raised central portion unevenly but very densely covered with nodose to tubercular protuberances (only the lower outer portion and the centre with distinctly less sculpturing). Colour uniformly greyish mid brown, the outer margin of the micropylar plate and the micropylar cup dark brown. Measurements [mm]: Length incl. operculum 3.3, length 3.1, width 1.9, height 2.3, length of micropylar plate 2.1.

Remarks. – Breeding was attempted in Europe with eggs obtained from specimens collected at Ifugao by T. Heitzmann ( Philippines) and Albert Kang ( Singapore) in October 2013 but did not succeed.

Distribution. – Luzon, endemic. N-Luzon:Province Ifugao (Central Cordillera, Cambulo trail, 1750 m [IMQZ, RBINS, FH – type locality]); Province Ifugao [TB].