Brasidas rehni, Hennemann, 2023

Brasidas rehni View in CoL n. sp.

( Fig. 18 & 70 O-P)

ZooBank: https://zoobank.org/ F92C8F80-A476-4495-A0D4-1CC954EB06F9

Euobrimus cavernosus, Rehn & Rehn, 1939: 449 View in CoL , pl. 31: 8 (♂), 36: 38 (♀), 38: 44 (♀ metasternum).

HT, ♀: Siargao Philippin; Euobrimus cavernosus (Stal) 1938 View in CoL , Det. J.W.H. Rehn, Hebard Cln. 19 [ ANSP] .

PT, ♀: Siargao Philippin; Euobrimus cavernosus (Stal) 1938 , Det. J.W.H. Rehn, Hebard Cln. 19 [ ANSP] .

PT, ♂: Siargao Philippin; Euobrimus cavernosus (Stal) 1938 , Det. J.W.H. Rehn, Hebard Cln. 19 [ ANSP] .

Differentiation. – This large new species is morphologically closest and very similar in general shape, appearance and spination to B. viscayanus Rehn & Rehn, 1939 from Mindanao, but differs by having all elements of the head and body armature notably less developed as well as the much smaller and rather triangular (♀, Fig. 70O) or elliptical (♂, Fig. 70P) metasternal pseudo-foramina. Females may also be separated by having the anterior pair of spines on the abdominal terga II-V smaller or at best equal in size to the remaining tergal spines (larger than all others in viscayanus ), the posterior meso- and metanotals cristate (simple spines in viscayanus ), the projections of the praeopercular organ much smaller and rather spinose and the posterior margin of the anal segmentand apex of the epiproct less indented. The smooth surfaced ♂ of this new species can readily be distinguished from those of viscayanus by lacking the distinct pair of anterior mesonotals ( Fig. 18E), having the posterior meso- and metanotals large, simple and spinose and the meso- and metapleurals strong and simply but short and only tuberculate (distinct spines with tuberculated base in viscayanus ). The green medio-longitudinal streak on the meso- and metanotum and basal abdominal terga resembles B. manobo n. sp. and B. samarensis Rehn & Rehn, 1939 , but the strongly reduced armature of the head and thorax and lack of anteriors on the mesonotum readily separate ♂ of this new species.

Etymology. – Named in honour of James Abram Garfield Rehn (1881-1965), an American entomologist and specialist on the Orthoptera, who worked at the Academy of Natural Sciences of Philadelphia, U.S.A., and must be regarded one of the most outstanding workers on the taxonomy of Phasmatodea of his time. He is well-known for his very accurate work and descriptions and was the first to present an in-depth study of the Philippine Obriminae stick insects, providing us with an elaborate and well usable acanthotaxy for this clade, which is also applied for species descriptions herein.

Description ♀ ( Fig. 18 A-C)

Form and colouration. – Size large (body length103.0- 112.3 mm), form rather slender with the elements of armature quite poorly developed if compared to congenerics;body surface otherwise moderately granular and the meso- and metanotum and basal abdominal terga with a fine medio-longitudinal carina. Colouration of the holotype fairly plain fuscous withsome dark ochre on the head, pronotum and posterior portions of the meso- and metathorax;the largest spines of the thorax ochre and the granules tipped with black. Limbs with a slight greyish wash. The paratype slightly lighter in colour with some grey and a slight greenish hue on thorax.

Head. – Scarcely longer than wide, subrectangular with vertex fairly rounded, convex and all the armature rather poorly developed; supra-antennals and supra-orbitals small and tuberculate, supra-orbital series represented by two low conical tubercles and two pairs of occipital medials slightly enlarged; the four coronals more pronounced, strong but low and conical; occiput otherwise unevenly tubercular. Genae only with 2-3 gular Eyes moderatelyprojectingandtheir diameter corresponding to abouthalf the length of gena. Antennae broken in both available examples (but number of joints believed to be 25 as in ♂); scapus compressed dorsoventrally and roundly rectangular in outline, pedicellus globose, III notably longer than pedicellus and gradually constricting towards apex, III very short and the following gradually increasing in the length.

Thorax. – Pronotum slightly longer and as wide as head, basically rectangular in outline but with a distinct pre-median concave excavation laterally; notably longer than wide. Surface unevenly granular and only armed with a moderately developed tubercular pair of post-medials just behind the gently arched and moderately impressed transverse median sulcus; otherwise only the antero-laterals somewhat more pronounced but small conical. Mesothorax slightly gradually widening towards the posterior, elongate and about 2.6x longer than prothorax. Mesonotum parallel-sided and 2.5x longer thanwide;anteriormesonotals, medials and post-medialsallspinose butsmall and the lateral margins with a moderately enlarged and conical medio-lateral; posterior mesonotals small but strong, spinose and cristate. Posterior metanotoals like posterior mesonotals but metanotum without any notably enlarged tubercles. Mesopleurae with a rather prominent spinose antero-lateral, a slightly smaller medio-lateral and two posterior-laterals;meso-pleural rather small and tuberculate. Metapleurae moderately expanded and rounded in posterior half and armed with about eight just slightly subequally sized spines, the metapleural small, tuberculate. Mesosternum smooth except for about six fairly distinct and spinose mesosternals close to lateral margins. Metasternum only with three small metasternals; the pseudo-foramina small, transversely triangular, deep and open holes ( Fig. 70O).

Abdomen. – Median segment distinctly transverse with anterior widely angular, only set with a small pair of tubercular medials. Segments II-VII roughlyuniform inwidthand length andabout1.6x widerthanlong.Terga II-V with fairly distinct, spinose anteriors, medials, second paired posteriors and medio-laterals; VI-IX unarmed and only with a medio-longitudinal carina, which becomes increasingly pronounced towards apex of abdomen and is protruded to form a low, dentiform posterior process on VIII and IX ( Fig. 18J). Sterna smooth except for a small medio-lateral pair of spiniform tubercles on II and III; praeopercular organ on sternum VII formed by a shallow median notch of posterior margin and pair of obtusely conical swellings. Anal segment longer than wide, obtusely and weakly tectate longitudinally, the lateral margins with a concave median excavation and the posterior margin rather weakly indented medially. Epiproct about 1.3x longer than anal segment, weakly tectate and slightly gradually narrowing towards a narrow but obtuse and weakly notched apex ( Fig. 18K). Subgenital plate elongate, lanceolate, distinctlykeeled inthe apical half and slightlysurpassing epiproct; the apex triangular and down-curved ( Fig.18J).

Legs. – Relatively slender with all the dentationsrather weakly developed, basal flexure of profemora distinct. Profemora with three small spiniform teeth in apical half of two ventral carinae; dorsal carinae with a few small dentations. Meso- and metafemora basically with about six teeth on all four carinae, these more pronounced and gradually increasing in size towards apex on ventralcarinae. Medioventral carina of meso- and metafemora notable and with 6-8 small spiniform tubercles, which disappear towards the apical one-third of femur. Meso- and metatibiae with rather minute dentations on ventral – A. ♀ holotype habitus, dorsal view. – B. ♀ holotype habitus, lateral view. – C. ♀ holotype habitus, ventral view. – D. ♂ paratype habitus, dorsal view. – E. ♂ paratype habitus, lateral view. – F. Terminalia of ♂ paratype in lateral view. – G. Terminalia of ♂ paratype in ventral view. – H. Terminalia of ♂ paratype in dorsal view. – J. Terminalia of ♀ holotype in lateral view. – K. Terminalia of ♀ holotype in dorsal view. – L. Terminalia of ♀ holotype in ventral view.

carinae, smooth dorsally. Probasitarsus almost as long as three proceeding tarsomeres; meso- and metabsitarsus slightly shorter.

Measurements [mm]. – Body103.0-112.3, pronotum 7.1-7.3, mesonotum 18.9-20.3, metanotum 9.0-9.7, median segment 4.6-4.9, profemora 18.0-20.7, mesofemora 16.2-18.4, metafemora 19.5--25.0, protibiae 20.0-22.3, mesotibiae 17.2-19.0, metatibiae 26.4-28.6,antennae -.

♂ ( Fig. 18 D-E)

Form and colouration. – Size large (body length 72.8 mm), form rather slender for the genus with the elements of armature poorly developed if compared to congenerics, except for the large but simple and spinose posterior meso- and metanotals; body surface otherwise conspicuously smooth and just weakly granular. Colouration plain buff with the dorsal portions of the meso- and metanotum rather russet; fuscous with faint darker mottling; meso- and metanotum and three basal abdominal terga with a faint dark green medio-longitudinal streak, which is most pronounced on the metanotum; the posterior meso- and metanotals, meso- and metapleurals and pair of prothoracic spines tipped with dark brown.Limbs buff with the spines darker brown.

Head. – Roundly subrectangular and scarcely longer than wide with vertex flattened and just weakly swollen medially; surface minutely and unevently tubercular and only the four coronals and a pair of occipital medials enlarged, but flat and obtusely conical; supra-antennals small, tubercular and supra-orbitals minute. Genae merely with 2-3 gulars that are represented as node-like granules. Eyes fairly large, projecting hemispherically and their diameter corresponding to 1.7x length of gena. Antennae with 25 joints and reaching to anterior of abdominal segment VI; scapus compressed dorsoventrally and oval in outline, pedicellus globose, III notably longer than pedicellus, IV very short and the following gradually increasing in the length with the median antennomeres strongly elongated.

Thorax. – Pronotum about as long but slightly wider than head and with a distinctsemi-circularpre-medianexcavation;shape subquadrate. Justbehindthe rather shallow and almost straight tranverse median sulcus armed with a prominent pair of fairly acute medial spines; otherwise only the antero-lateral pronotals developed and slightly spiniform. Mesothorax slender and notably widened and inflated in posterior portion, elongate and about 3.6x longer than prothorax. Mesonotum unarmed except for strong, but simple and spinose posterior mesonotals. Metanotum slightly trapezoidal in outline, somewhat inflated posteriorly and the posterior metanotals similar but slightly larger than posterior mesonotals;surface otherwise unarmed.Mesopleurae unarmed except for a low, hump-like antero-lateral and a stout, obtusely spinose mesopleural. Metapleural similar to mesopleural but metapleurae otherwise with about six tubercles, the three laterals of which are small, tubercular and the three supra-coxals conical and rather subspinose. Mesosternum smooth except for some rather small and granular mesosternals. Metasternum with a shallow granulose central swelling and otherwise sparsely granular; the pseudo-foramina of average size, open and oval holes that cover about half of the distance from the anterior margin of the metasternum to the metacoxal ( Fig.70P).

Abdomen. – Median Median segment trapezoidal in shape and unarmed. Segments II-IV slightly increasing and V.VII decreasing in length with IV longest and 1.3x longer than wide; II and VII distinctly trapezoidal and III-VI roughyl uniform in diameter. Terga unarmed. Sterna II-VII with a fine medio-longitudinal carina and only II witha small pair of anterior tubercles;all others smooth. Terga VIII and IX transverse and weakly tectate medio-longitudinally, VIII with an obtuse and shallow hump-like posteromedian protuberance.Anal segment somewhat shorter than IX, deflexed in basal half, narrowed posteriorly and the posterior margin broadly bi-lobed with a deep and broadly triangular median emargination ( Fig. 18H); the posterolateral angles ventrally with a few small denticles. Epiproct small, triangular and just slightly projecting beyond posteromedian emargination of anal segment. Vomerbasicallytriangularinoutlinewithafairly strongterminal hook thatis slightly arched towards the right. Cerci small, compressed laterally and gently in-curved. Poculum very large, bulgy, roundly angular ( Fig. 18F) and with an obtuse medio-longitudinal keel in the vertical posterior portion; posterior margin triangular and roughly reaching to tip of anal segment ( Fig. 18G).

Legs. – Relatively slender, basal flexure of profemora distinct. Profemora with three triangular teeth in apical half of two ventral carinae; dorsal carinae only with a few minute dentations. Meso- and metafemora only with a few small teeth dorsally; the two outer ventral carinae each with about seven teeth that notably increase in size with the two apical ones strong and spinose; medioventral carina of meso- and metafemora notable and with 6-8 granules, that gradually disappear towards the apical one-third. Meso- and metatibiae with numerous small and uneven dentations ventrally, smooth dorsally. Basitarsus about as long as three proceeding tarsomeres taken together.

Measurements [mm]. – Body 72.8, pronotum 4.9, mesonotum 17.0, metanotum 8.5, median segment 3.8, profemora 16.7, mesofemora 15.4, metafemora20.5, protibiae 17.0, mesotibiae 14.3,metatibiae 20.6, antennae 58.5.

Remarks. – This species was misidentified by Rehn & Rehn (1939: 449) as Euobrimus cavernosus . Examination of the specimens in the collection of ANSP has shown them to be a separate as yet undescribed species. It is so far only known from Siargao, a small island off the north-eastern coast of Mindanao. Eggs unknown.

Distribution. – Siargao, endemic.