Tisamenus hebardi ( Rehn & Rehn, 1939 )

Tisamenus hebardi ( Rehn & Rehn, 1939) View in CoL

( Fig. 20-21, 46 M-N)

Ilocano hebardi Rehn & Rehn, 1939: 461 View in CoL , pl. 31: 3 ( ♀).

HT, ♀: Baguio, Benguet, Luzon. P.I, ( E.H. Taylor), VII.1923; Ilocano hebardi Rehn View in CoL + Rehn Type H.1343; Data Base Serial No. Assigned as Type No. September 2008. Type # 9130 [ ANSP] .

- Otte, 1978: 79. ( Type data) A. Dorsal view (Palanan, Cagayan Valley, Isabella Province, East Luzon – Arrow indicating the single metapleural that distinguishes T. draconinus from the very similar T. napalaki n. sp.) [FH 1104-4]. B. Dorsal view (captive reared from Callao Cave, Cagayan Province, North Luzon) [FH 1104-44]. C. Dorsolateral view (Palanan, Cagayan Valley, Isabella Province, East Luzon) [FH 1104-4]. D. Dorsolateral view (captive reared from Callao Cave, Cagayan Province, North Luzon) [FH 1104-44]. E. Lateral view (Palanan, Cagayan Valley, Isabella Province, East Luzon) [FH 1104-4]. F. Lateral view (captive reared from Callao Cave, Cagayan Province, North Luzon) [FH 1104-44]. G. Ventral view (Palanan, Cagayan Valley, Isabella Province, East Luzon) [FH 1104-4]. H. Anteroventral view of right hind leg (arrows indicating the characteristic three ventral teeth of the metatibiae). I. Ventral view of mesofemur showing the characteristic incrassate base. J. Terminalia in lateral view. K. Terminalia in dorsal view. L. Terminalia in ventral view. M. Closeup of head, pro- and mesonotum (captive reared from Callao Cave, Cagayan Province, North Luzon). N. Closeup of pro-, meso- and metasternum (captive reared from Callao Cave, Cagayan Province, North Luzon).

- Zompro, 2004: 208, fig. ( ♀).

- Otte & Brock, 2005: 164.

- Hennemann et al., 2016: 21, fig. 60 ( ♀).

Tisamenus hebardi, Bank et al., 2021: 13 View in CoL .

- Brock & Büscher, 2022: 521.

- Hennemann, 2023b: 128.

Material examined

3 ♀, 5 ♂, 1 egg: Coll.R.I.Sc.N.B., Philippines, Luzon , Mt Prov.Sagada, Mt Polis, 2000m +, 16°57’40’’N 121°1’18’’E, Mossy For., 15.iv.2014, IG: 32700, Mission Leopold III Funds, Constant J., Bresseel J. & co. [ RBINS] GoogleMaps ;

1 ♀ (penultimate instar): Coll. R.I.Sc.N.B., Philippines, Ifugao, XI.2013, Leg. T. Heitzmann [ RBINS] .

Differentiation. – This is the smallest representative of the genus and particularly distinctive in that the cephalic, thoracic and abdominal armature is much reduced to almost entirely wanting. In both sexes the head merely bears a pair of low sub-laminate post-orbital crests and there are no supra-orbital spines, the pronotum only has two posteriorly convergent rows of low granules ( ♀, Fig.20E) or tubercles ( ♂, Fig. 21G), the meso- and metapleural supra-coxals are only represented by low rounded nodes and there are no hints of posteriors on the abdominal terga. In ♀ the mesonotal triangular area is merely indicated by two low posteriorly convergent carinae that anteriorly terminate in an obtuse tubercle, whereas the triangular area is more evident in ♂ with the carinae somewhat produced triangularly at the anterolateral angles; in both sexes the triangular area scarcely reaches to the middle of the mesonotum. Overall, this species comes morphologically closest to T. charestae n. sp. and T. ranarius (Westwood,1859) but both species are notably larger and furthermore separable by the characters mentioned above. The eggs ( Fig. 46 M-N) readily differ from those of all other known eggs of congenerics by the very short posterior extensions of the micropylar plate, which only form two rounded lobes that hardly reach towards the lateral surfaces of the capsule.

Description

♂ ( Fig. 21)

Form and colouration. – Size very small (body length 18.1-18.9mm); form rather stout, legs of average length for the genus with only the metafemora weakly incrassate basally; elements of armature essentially as in ♀ but much more pronounced and obtuse, the surface texture of body minutely sub-granulose. Mesothorax almost rectangular with the pleurae gently convex pre-medially. General colour fuscous with all the elements of cephalic and thoracic armature and the medio-longitudinal keel of dorsal body surface buff to mid brown, posterior portion of meso- and most of metasternum tawny and the meso- and metafemora slightly lighter ventrally. Antennae dark brown with the terminal twelve joints dark ochre to orangey brown; the terminal antennomere black at the tip ( Fig. 21G).

Head. – Large, roundly sub-rectangular and scarcely longer than wide with the genae roughlyparallel-sided but weaklyconvex.Armature essentially as in ♀; the supra-orbitals prominent sub-laminate, obtusely tri-tubercular crests with the conical second point largest and covering most of the distance from back of eye to coronals;supra-antennals representedby a pair of low but wide nodes; occipitals sub-obsolete and the median and lateral coronals rather low and obtusely tuberculate. Genae only supplied with two very small, granular gulars posteriorly ( Fig. 21G). Eyes of moderate size, hemispherical andtheir diameter corresponding toroughly half the length of gena. Antennae consisting of 24 joints, strong and perlamorph with all the antennomeres, except for the three basal ones and the terminal one short and globose to barrel-shaped; scapus trapezoidal and longer than wide, pedicellus much narrower and about two-thirds as longas scapus and round in cross-section; III elongate and slightly longer than pedicellus, IV only one-third the length of III, following joints up to about XI very slightly increasing in length, then decreasing with the terminal antennomere much elongated and almost as long as four preceding joints taken together.

Thorax. – Pronotum trapeziform, transverse andnotably wider thanlong with anterior margin triangularly concave; triangular area distinct with posteriorly convergent margins obtusely nodose, the anteriors large and expanding over entire pre-sulcal area, obtuse tri- or quadri-tubercular; transverse median sulcus distinctly indented ( Fig. 21G). Mesothorax basically rectangular with a slight narrowing pre-posteriorly, about 2x longer than prothorax and scarcely longer than wide. Mesonotum rectangular with lateral margins shallowly concave and the pre-posterior lateral areas somewhat gibbose, 1.5x longer than wide; the triangular area much more distinct than in ♀, rather large, attaining middle of notum, and roughly an isosceles triangle; disk deeply concave in centre and the very gently arched converging outer margins weakly granular and increasingly raised towards the anterior angle; the anterior margin swollen and with two low median nodes ( Fig. 21G); posterior portion of mesonotum with a shallowly granular medio-longitudinal bulge posterior to triangular area. Mesopleurae strongly expanded and gently convex in the anterior two-thirds with a slight narrowing pre-posteriorly; laterals much more pronounced than in ♀ and represented by four obtuse low tubercles; mesopleural a rather small and low conical tubercle. Metanotum about as long as wide with posterior margin distinctly concave and with a shallowly granular medio-longitudinal bulge. Metapleurae with laterals just very weakly indicated, the metapleural a somewhat more pronounced low swelling and the supra-coxal angle with a short and obtuse bifid supra-coxal tubercle. Probasisternum with a widely spaced pair of distinct nodes; the sensory areas of prosternum weakly developed. Mesosternum densely and unevenly granular and with faint indications of three longitudinal carinae; metasternum only with a rather shallow medio-longitudinal carina ( Fig. 21D).

Abdomen. – Median segment almost semi-circular in outline, obtusely carinate medio-longitudinally. Segments II-VII slightly sub-uniform in length but roughly uniform in width, all transvers with V longest;II sub-trapeziform. Terga II-VII all with a shallow medio-longitudinal carina that is indicated by about four low granules and with paired second posteriors merely represented by low nodes. Sterna II-VII with a faintly indicated medio-longitudinal carina. Terga VII-IX with a posteromedian swelling that is formed by a protrusion of the medio-longitudinal carina and is most prominent and obtusely conical on IX ( Fig. 21E); the latter about 2x wider than long.Anal segmentslightlywider than long but noticeably longer than preceding segment; sub-rectangular, moderately declining and with lateral margins somewhat deflexed at the median angle; posterior margin with a wide, concave emargination and the outer angles obtusely rounded. Epiproct transverse, widely rounded. Vomer black, broad with base transverse and the terminal hook somewhat displaced towards the right, short, weakly arched inwards and sharply up-curved; the ventral surface of basal portion shallowly concave medially ( Fig. 21F). Poculum bulgy,angularly cup-shaped with a very broad and weakly bi-labiate posterior flange of the free upper margin, that reaches back no more than about one-quarter the way along anal segment ( Fig. 21 E-F).

Legs. – Moderately stocky, much heavier with armature much more pronounced than in ♀; the armature of front and mid legs however obtuse, which concerns to the dorsal dentate swellings in particular. Pro- and mesofemora about as long as mesothorax, metafemora reaching to posterior margin of abdominal segment V and metatibiae almost reaching to tip of abdomen. Pro- and mesofemora with only two blunt teeth in apical one-third of outer ventral carinae distinct;the four dorsal protrusions of all three femora uneven, obtuse and scarcely dentiform. Metafemora with ventral-basal swelling very shallow and armedwith four obtusely spiniform teethon ventral carinae, the apical ones of which are more pronounced. All four carinae of metatibiae with 3-4 obtuse swellings, only the apical ventral one of which is weakly dentiform. Basitarsi short and about as long as following two tarsomeres taken together.

Measurements [mm]. – Body 18.1-18.9, pronotum 1.7, mesonotum 2.8-2.9, metanotum 1.4-1.5, median segment 1.0-1.1, profemora 3.1-3.2, mesofemora 3.0, metafemora 4.1-4.2, protibiae 3.6–3.8, mesotibiae 3.1-3.4, metatibiae 4.0-4.6, antennae 6.1-6.3.

Variability. – No significant morphological variability is seen in the series of specimens at hand. It is however noteworthy that that the holotype ♀ in the collection of ANSP has all of the elements of cephalic and thoracic armature including the triangular mesonotal area less developed than all other examples and is of a lighter tawny general colour with a broad, washed fuscous medio-longitudinal streak along the dorsal body surface ( Fig. 21I). The less developed triangular mesonotal area certainly was one reason that prompted Rehn & Rehn (1939: 460) to describe a new genus for this diminutive species. Although these authors did not mention the presence of a triangular area on the mesonotum, careful examination of the holotype shows there to be two weakly indicated convergent carinae that vanish some distance before they would join. In the other specimens at hand these two carinae are much more distinct but also don’t merge posteriorly. Interestingly, and representing a state that is unique within the whole of Tisamenus , is that the triangular mesonotal area is relatively much larger and different in shape and texture in ♀ than in ♂. Body length of ♀ 28.2-31.0 mm.

Egg ( Fig. 46 M-N)

Small for the genus; capsule ovoid but widest somewhat below anterior margin, the dorsal surface just slightly more convex than ventral surface, slightly oval in cross-section, higher than wide and capsule 1.5x longer than wide. Anterior margin somewhat inflated and covered with a collar of fringy excrescences and the capsule with a shallow constriction below anterior margin. Surface densely but very minutely granular and unevenly covered irregularly shaped peg-like or fringy protuberances; these most distinct and numerous at polar-area and wanting in the constricted anterior region. Micropylar plate small but broad and staying clearly away from the anterior margin of the capsule and the two posterolateral extensions small and obtusely rounded; the posterior portion with a 70° V-shaped indention that has a small bowl-shaped micropylar cup in centre. Outer margin of plate marked by an irregularly granular bulge; only the interior portion of surface in lower half with sculpturing similar to that of capsule; the outer portions destitute of noticeable sculpturing. Median line shallow longitudinal, granular carina that almost reaches to the polar end of capsule. Operculum oval with the central portion gibbous and densely covered with a broad rim of fringy excrescences; similar but shorter excrescences along outer margin and a few irregular but radially directed carinae or rugulae in between. Colour quite uniformly greyish mid brown, the outer margin of the micropylar plate, micropylar cup and the protuberances of the capsule dark brown. Measurements [mm]: Lengthincl. operculum 2.9, length 2.7, width 1.8, height 2.0,length of micropylar plate 1.8.

Remarks. – This diminutive mountainous species was generically misinterpreted by Rehn &Rehn (1939: 460), who described the genus Ilocano to comprise hebardi and T.ranarius (Westwood,1859) . These authors suggested an intermediate position between the genera Tisamenus (referred to as Hoploclonia Stål, 1875 ) and Eubulides Stål, 1877 but molecular data have clearly shown hebardi to be deeply nested within species of Tisamenus , why Ilocano was synonymised with Tisamenus by Bank et al. (2021:14). The previously unknown ♂ and egg are her formally described and illustrated in detail. The penultimate instar ♀ in the collection pf RBINS has the mesopleural A. Dorsal view. B. Dorsolateral view. C. Lateral view. D. Ventralview. E. Closeup of head, pro- and mesonotum. F. Terminaliain lateral view. G. Terminaliain dorsalview. H. Terminalia inventralview. I. Live ♀ with a broad ochraceous medio-longitudinal dorsal streak on most of body near San Antonio, Dupax del Norte, Province Nueva Vizcaya, North Luzon [© Albert Kang https://inaturalist.ca/observations/57616113].

armature much more developed than adult specimens and represented by five fairly prominent spiniform but obtuse tubercles ( Fig. 21 J-K).

Breeding was attempted in Europe from stock collected by Joachim Bresseel (RBINS), Jérôme Constant (RBINS) and Thierry Heitzmann ( Philippines) in a cloud forest habitat at an altitude of over 2000 metres near Sagada, Mount Polis, Mountain province, N-Luzon in April 2014. While specimens could be maintained alive on bramble ( Rubus spp ., Rosaceae ) in Belgium breeding was not successful.

Distribution. – North Luzon: Province Benguet ( Baguio [ANSP – type locality]); Mountain Province (Sagada, Mount Polis 2000 m [RBINS]); Province Ifugao (unspecified [RBINS]; Banaue [photographic records by Albert Kang: https://inaturalist.ca/observations/ 57719470, https://inaturalist.ca/observations/57611612, https://inaturalist.ca/ observations/57611537]; Dupax del Norte San Antonio [photographic record byAlbert Kang:https://inaturalist.ca/observations/57616113]).