Tisamenus hystrix ( 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 : 42-45

Tisamenus hystrix ( Rehn & Rehn, 1939)

( Fig. 23-24)

Hoploclonia hystrix Rehn & Rehn, 1939: 469 , pl. 32: 16 (♂).

HT, ♂: Island Sibuyan, Baker; Type No. 53313 U.S. N.M.; Hoploclonia hystrix Rehn & Rehn Type [ USNM] ;

PT, ♀ (penultimate instar): Island Sibuyan, Baker; Type No. 53313 U.S. N.M.; Hoploclonia hystrix Rehn & Rehn Allotype Paratype [ USNM] .

Tisamenus hystrix, Zompro, 2004: 206 .

- Otte & Brock, 2005: 335.

- Brock & Büscher, 2022: 521.

- Hennemann et al., 2016: 134, figs. 70a-c (egg).

- Hennemann, 2023b: 128.

Material examined

2 ♀, 1 ♂: Coll. R.I.Sc.N.B., Philippines, Sibuyan , VI.2014, A. Kang [ RBINS] ;

1 ♂, 1 ♀: Philippinen, Province Romblon, Sibuyan Island , localcollector VIII. 2012 [ FH, No’s 1263-4 to 5] ;

1 ♀, 2 ♂: ex Zucht Holger Dräger 2021, Herkunft: Philippinen, Sibuyan Id., Rombon-Islands, leg. A Kang VI.2014 [ FH, No’s 1263-1 to 3] .

Differentiation. – Namely, this distinctive species is characteristic for having all the elements of armature of the head and body very long, slender and acutely spinose. Morphologically it is closest to T. clotho ( Rehn & Rehn, 1939) and T.lachesis ( Rehn & Rehn, 1939) but it is an endemic of Sibuyan Island and therefore geographically separated from these two Luzonian species. From clotho ♀ may be

A. Dorsal view. B. Dorsolateral view. C. Lateral view. D: Ventral view. E. Anteroventral view of right hind leg. F. Terminalia in dorsal view. G. Terminalia in ventral view. H. Closeup of head, pro- and mesonotum.

separated by the slightly smaller dimensions but notably slenderer shape with slenderer and relatively longer legs ( Fig. 23 A-E), the metatibiae of which roughly reach to the apex of the ovipositor.There is a prominent pair of posteriors on abdominal terga II-V but there often is a pair of posteriors also on abdominal terga VI and VII and often there also is a variably sized triangular posterior mesal on all abdominal terga and a small pair of inter-posterior mesonotaltubercles on the meso- and metanotum, whereas in clotho there are never posteriors on VI-VII and the posterior mesal is small and rather conical. Males are easily distinguished from those of clotho by the slenderer shape and more elongate legs with the metafemora in particular much lessincrassate ( Fig.24 A-E), the presence of a spinose pair of inter-posterior meso- and metanotals ( Fig. 24B, E) and a pair of distinct posteriors on abdominal tergum V and occasionally also VI (only on II-IV in clotho ) and lack of the ventro-basal swelling of the metafemora ( Fig. 24F). From the notably larger lachesis both sexes of this species are easily distinguishable by the stockier overall shape, relatively longer body segments, more widened meso- and metapleurae and smaller mesonotal triangular area, which is scarcely longer than it is wide across the anterolateral angles and not reaching the middle of the mesonotum (distinctly longer than wide and reaching beyond the middle of the mesonotum in lachesis ). Moreover, lachesis never has definite posteriors on abdominal terga VI and VII and the inter-posterior meso- and metanotals may be wanting. The eggs resemble most closely those of clotho but differ by lacking the anterior constriction of the capsule seen in eggs of clotho , having the posterolateral extensions of the micropylar plate shorter and broader and having the sculpturing of the capsule more pronounced than in clotho . From the eggs of lachesis they differ by the shorter and considerably fewer fringes or setae of the capsule surface, longer and

A. Dorsal view. B. Dorsolateral view. C. Lateral view. D. Ventral view. E. Dorsal view [FH 1263-4]. F. Terminalia in lateral view. G. Terminalia in dorsal view. H: Terminalia in ventral view. I. Closeup of pro-, meso- and metasternum. J. Closeup of head, pro- and mesonotum.

broader posterolateral extensions and narrower anterior portion of the micropylar plate.

Variability. – The wild ♀ in the authors collection (FH No. 1263-4, Fig. 23E) is remarkable for having an additional conical spine in the posterior half of the outer carinae of the mesonotal triangular area, the triangular posterior mesal of the abdominal terga strongly developed and almost as large as the posteriors of the corresponding terga, a small spine at the posterolateral angle of terga II-V and having a distinct spinose pair of posteriors also on terga VI and VII. Body lengths ♀ 48.0-52.0 mm, ♂ 34.5-37.5 mm.

Remarks. – In the past there has been some discrepancy regarding to the type-locality of this species. Rehn & Rehn (1939: 469) originally described Hoploclonia hystrix from a ♂ and immature ♀ for which they stated the locality to be “Sibulan, Oriental Negros, Negros, Philippines. (Baker)”. Based on this published information Lit & Eusebio (2005: 209) and Lit (2010: 331) regarded hystrix as to be from the island of Negros. However, the original locality label attached to the two type specimens in USNM states “Island Sibuyan, Baker”, thus it is clear that the specimens actually originate from the island of Sibuyan and not from Negros. This is supported by further specimens of hystrix that have recently become available for examination, all of which are from Sibuyan. Illustrations of the eggs were presented by Hennemann et al. (2016: 134, Fig. 70a-c). Unfortunately, the examined example in the collection of O. Zompro (Berlin) could not be re-examined for providing a proper description as well as photographs and no eggs were saved from the culture stock. From the known eggs of the genus, this egg most closely resembles that of T. napalaki n. sp. Detailed illustrations of both sexes and a photographic documentation are here provided. The ♀ was only described from an immature by Rehn & Rehn (1939: 471), but since the morphology of the adult insect essentially corresponds to that of large immatures no redescription but only detailed illustrations of the adult ♀ are presented herein.

A culture was maintained for a few generations that was given rise by specimens collected near San Fernando, Romblon, Mount Guiting Nature Park on the island of Sibuyan in June 2014 by Albert Kang ( Singapore). Meanwhile the culture has vanished and it has not been given a Phasmid Study Group culture number.

Distribution. – Sibuyan (unspecified [USNM – type locality, FH, RBINS]; Romblon, San Fernando, Mount Guiting Nature Park [FH; photographic record by Albert Kang: https://www.jungledragon.com/image/ 50821/spiny_phasmid_couple.html andhttps://inaturalist.ca/observations/62277997]).