Tisamenus alviolanus Lit & Eusebio, 2010

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 : 11-13

Tisamenus alviolanus Lit & Eusebio, 2010

( Fig. 3)

Tisamenus alviolanus Lit & Eusebio, 2010: 328 , figs. 2a-f.

HT, ♀: Mt Kanlaon, Sitio Napatagan, Barangay Mailom , Bago City , Negros Occidental, 17-24.vi.2007, P.A. Alviola & E.A. Cosico [ UPLB, No. PHA-00137] ;

AT, ♂: same data as HT [UPLB, No. PHA-00138];

AT, 3 ♀, 1 ♂: same data as HT [ UPLB, No’s. PHA-00139 to 00142] .

- Brock & Büscher, 2022: 521.

- Hennemann, 2023b: 128.

Material examined

1 ♀, Philippinen, Central Visayas, Negros Oriental, Don Salvador Benedicto , local collector V.2012 [ FH, No. 1258-1] ;

2 ♀, 1 ♂, Coll.R.I.Sc.N.B., Philippines, NegrosOrient., Dumaguete , IX.2014, local collector, I. Lumawig [ RBINS] .

Differentiation. – This species is utterly close to the Luzonian T. cervicornis Bolívar, 1890 and based on the few known specimens of alviolanus , morphological distinction is very difficult, but both sexes are smaller on average than either cervicornis and alviolanus appears to be geographically separated since it is believed to be endemic on the island of Negros.Females merely differ by the more narrowed apex of the epiproct ( Fig. 3M) and ♂ are separable from those of cervicornis only by the more pronounced tuberculate mesopleural laterals and the less swollen ventro-basal portion of the metafemora ( Fig. 3F). Judging from the illustrations presented by Lit (2010: 329) the eggs are very similar to those of cervicornis and only differ by the slightly bulgier overall shape, broader, parallel-sided and more rounded dorsal extension (slightly narrowing towards the apex in cervicornis ) and comparatively shorter ventro-lateral extensions of the micropylar plate, which do not attain the longitudinal middle axis of the capsule (projecting over middle axis in cervicornis ).

Remarks. – The four specimens at hand for examination from the collection of RBINS and the collection of the author, differ from the type specimens by the slightly larger dimensions, more distinct and spinose meso- and metapleural supra-coxals and noticeably more pronounced second paired posterior spines of abdominal terga II-V. Moreover, the ♂ from Dumaguete in RBINS has the lateral margins of the mesopleurae rather gently concave than convex in outline like in the allotype. As stated above, and taking the variability possessed by the few specimens available into account, distinction from T. cervicornis is close to impossible and the distinctive features mentioned above may well lie within the range of variability of cervicornis . It is only the distribution on Negros and the slight differences in egg

A. ♀ dorsal view. B. ♀ dorsolateral view. C. ♀ lateral view [ RBINS]. D . ♂ dorsolateral view. E. ♂ lateral view. F. ♂ ventral view. G. Closeup of head and thorax of ♀ in dorsolateral view. H. Closeup of head and thorax of ♂ in dorsolateral view. I. Closeup of pro-, meso- and metasternum of ♂. J. Terminalia of ♂ in dorsal view. K. Terminalia of ♂ in ventral view. L. Terminalia of ♀ in lateral view. M. Terminalia of ♀ in dorsal view [ FH 0118-64 ]. N. Terminalia of ♀ in ventral view. morphology, that induce keeping alviolanus as a separate species for now until more specimens become available and even DNA sampling can be conducted. Body lengths of ♀ 44.0- 46.8 mm, ♂ 27.4-34.0 mm.

Distribution. – Negros.Province Negros Occidental (Mount Kanlaon, Bago [UPLB– type locality];Don Salvador Benedicto [FH]); Province Negros Oriental (Dumaguete [RBINS]).