Obrimus bicolanus Rehn & Rehn, 1939

Obrimus bicolanus Rehn & Rehn, 1939 View in CoL

( Fig. 41, 44 A-D, 70R-S, 72H & 73N-O)

Obrimus bicolanus Rehn & Rehn, 1939: 428 View in CoL , pl. 32: 15, 38: 41.

HT, ♀ (penultimate instar): Bulusan , Sorsogon, Luzon, Philippines (W. Boettcher); Obrimus bicolanus Rehn View in CoL + Rehn, Type 1297, HebardCln;Data Base Serial No. assigned as Type No. September 2008, Type [ ANSP] .

- Otte, 1978: 79. (Type data)

- Zompro, 2004: 215.

- Otte & Brock, 2005: 228.

- Harman, 2015: 26. (Notes on origin of culture stock)

- Hennemann et al., 2016: figs. 21-22, 39, 45-46.

- Brock & Büscher, 2022: 521.

Material examined

19 ♀, 22 ♂, eggs: ex Zucht F. Hennemann 2011-2014, Philippinen, SOLuzon, Prov. Bicol, Sorsogon, Pocdol Mts., Mt. Pulog NP, Mt. Pulog X.2010 [ FH No’s 0730-1 to 41 & E] ;

2 ♀: Philippinen, S-Luzon Id., Bicol Region, Provinz Sorsogon, Pocdol Mountains , local collector X.2010 [ FH 0730-42 & 43] ;

1 ♂: Philippines, Luzon, Bicol, Mt. Osiao , Leg T. Heitzmann & A. Kang, X.2009 [ RBINS] ;

2 ♀, 1 ♂: Ex Breeding J. Bresseel 2012; Origin: Philippines, SouthEast Luzon, Bicol Province, Sorsogon, Pocdol Mts., Mt Pulog 2011, T. Heitzmann [ RBINS] ;

2 ♀, 1 ♂: Ex Culture Bresseel 2013; Origin: Philippines, Luzon , Sorsogon, Bicol Province , Pocdol Mountains , leg Heitzmann X.2010 [ RBINS] .

Differentiation. – In size and shape this species is fairly alike uichancoi whereas the strongly developed body spination strongly resembles bufo . From uichancoi , these ♀ may be separated by the distinct median mesonotals as well as the distinct medials and second paired posteriors of the abdominal terga I-VI, but having the pair of posterior mesal pronotals just weakly developed, and having the triangular median excavation of the anal segment notably smaller and narrower ( Fig. 41K). From the much larger bufo these ♀ differ by the somewhat stockier shape,lack of anterior pronotals ( Fig.41B), presence of second paired posteriors on abdominal terga II-VI, presence of a distinct post-median lateral spines on abdominal terga II-V ( Fig. 41A) and a differently shaped praeopercular organ, which consist of a pair of oval swellings near posterior margin of sternum VII ( Fig. 41L). Males strongly resemble those of bufo and basically agree in the head and body armature.They may however be distinguished by the shape of the anal segment, which is rather hexagonal in shape ( Fig. 41H, distinctly transverse in bufo ), has the posterior margin narrower and lacks the two pits near each posterolateral angle seen in bufo , as well as the much differently shaped vomer ( Fig. 72H), that has the entire apical half strongly constricted to form a very long and slender, spiniform terminal hook. The eggs ( Fig. 73 N-O) differ from those of bufo by the less inflated micropylar plate and the larger opercular angle (-25° vs. -15° in bufo ).

Variability. – The specimens examined show no noteworthy variability in the head and body armature other than slight variation in the developments of the spines.The variability is even less in ♂. The colouration of ♀ however varies from various tones of grey, ochre, drab and brown ( Fig. 44A) to dark green or olive and specimens are almost always to a variable degree irregularly flecked with darker tones of brown ( Fig. 44 B-C). Occasionally, there may also be some irregularly dispersed white dots on abdominal tergum IV / Fig. 44C). Males show some variation in the intensity of the pale creamor straw-coloured medio-longitudinal dorsal streak on the thorax and basal three abdominal terga as well as the ferruginous lateral surfaces of the mesothorax. Body lengths: ♀ 83.5-98.0 mm, ♂ 61.8-67.0 mm.

Remarks. – This species was described from a unique penultimate instar ♀ nymph from Bulusan, Bicol Province in the collection of ANSP.There have not yetbeen formal descriptionsof the adult ♀ and ♂ but since the species is being reared in captivity there are numerous pictures of live specimens available in the internet. Culture stock collected by Thierry Heitzmann ( Philippines) on Mount Pulog, Bicol Province in October 2010 was added to the Phasmid Study Group culture-list as culture No. 324. Infotrmation on the culture history and captive breeding was provided by Dräger (2014: 9). It is easy to rear in humid conditions and accepts various alternative food-plants in captivity including bramble and raspberry ( Rubus spp. , Rosaceae ), roses ( Rosa spp. , Rosaceae ), hazel ( Corylus avellana , Betulaceae ), oaks ( Quercus spp. , Fagaceae ), salal ( Gaultheria shallon , Ericaceae ) and hawthorn (Crategus spp., Rosaceae ). The eggs are described in detail below.

Egg ( Fig. 73 N-O). – Large, bulgy and of typical shape for the genus; capsule slightly arched, with a conspicuous constriction anteriorly and posteriorly and the polar area indented transversely; the dorsal surface much more convex than ventral surface. Surface smooth but very sparsely, minutely and rather irregularly pitted; a rim of somewhat larger pits along the anterior margin. Micropylar plate very slightly inflated and weakly raised above capsule surface, sculptured like capsule; shape broadly T-shaped with the median portion as well as the two lateral extensions rounded at the apex; posteromedian portion triangularly excavated and with a small bowl-shaped micropylar cup. Median line an obtuse keel that reaches to the anterior protrusion of polar area. Operculum circular, flat and pitted like capsule; opercular angle ca. -25°. Colour plain grey, the outer margin of the micropylar plate darker grey and the outer margin of the operculum blackish. Measurements [mm]: Length 5.4-5.5, width 3.7-3.8, height 3.9-4.0, length of micropylar plate 3.8.

Distribution. – South Luzon, Bicol Region, Province Sorsogon (Bulusan [ANSP – type-locality]; Pocdol Mountains, Mount Pulog [FH, RBINS]; Mount Osiao [RBINS]).