Pylaemenes gravidus ( Bates, 1865 ), 2023

Hennemann, Frank H. & Tirant, Stéphane Le, 2023, Stick and Leaf Insects of Morotai Island, Indonesia (Phasmatodea), Faunitaxys 11 (24), pp. 1-28 : 4-5

Pylaemenes gravidus ( Bates, 1865) rev. stat.

( Fig. 2)

Acanthoderus gravidus Bates, 1865: 343 . HT, ♀: Gil.; Wallace; gravidus Bates [OUMNH, No. 497].

Pylaemenes gravidus, Kirby, 1904: 400 .

Datames gravidus, Redtenbacher, 1906: 52 .

- Günther,1934:76.[Synonymised with Datames oileus (Westwood,1859) –in error]

- Otte& Brock,2005:297.[Listed s a synonym of Datames oileus (Westwood,1859) ]

- Hennemann,1998:124.[Listed s a synonym of Pylaemenes coronatus (Haan,1842) ] Datames aequalis Rehn, 1904: 89 . HT, ♀ (nymph): Obi Island, Moluccas; Datames aequalis Rehn , TYPE No. 5138 [ANSP]. n. syn.

- Kirby,1904:400.

- Redtenbacher,1906:51.

- Günther,1934:76.[Synonymised with Datames oileus (Westwood,1859) –in error]

- Otte,1978:78.

- Hennemann,1998:124.[Listed as a synonym of Pylaemenes coronatus (Haan,1842) ]

- Otte& Brock,2005:297.[Listed s a synonym of Datames oileus (Westwood,1859) ]

Material examined

Morotai

- 2 ♀, Indonesia, Morotai Island, North Maluku Regency, Daeo Majiko village , XI.-XII.2012 [coll. FH, No’s 1125–1 & 2] .

Halmahera

- 1 ♀, IDO: Halmahera NW, 7km S Jailolo , 200 m, 1°1’18’’N, 127°31’39’’E, 27.I.2006, leg. A. Weigel [ NMEG] ;

- 1 ♀ (nymph), INDON.: Halmahera NW, 10km S Jailolo , 200m, 26.I. 2996, leg. A. Weigel, plantage [ NMEG] .

Bacan

- 1 ♀ (nymph), INDONESIA, N-Molukken, Bacan , 10km E Labuha, 0°38’07’’N, 127°34’46’’E, 14.I.2006, leg. A Weigel, 120 m [ NMEG] .

Ternate

- 1 ♀ (nymph), IDO: N-Molukken, Ternate , Laguna lake, 45’44’’N, 127°21’6’’E, leg. A. Weigel [ NMEG] .

Differentiation. – Morphologically most similar and presumably closely allied to the Sulawesian P. moluccanus (Redtenbacher, 1906) with which it shares the reduced body armature. However, ♀ of gravidus (the only sex known) may readily be separated by the even less developed body armature, lack of a posterior pair of spines on the mesonotum, much smaller and less upright anterior pair of mesonotal spines, basically more conical and less distinctly spinose vertex and longer anal segment, that has the posterior protrusion significantly longer than wide and gradually narrowing, whereas it is wider than long and basally parallel-sided in moluccanus .

Comments. – The original description presented by Bates (1865: 343) is fairly detailed and shall not be extended here but is supplemented by a set of illustrations of the ♀, the only sex currently known. Günther (1934: 86) erroneously synonymised Bates’ species with Pylaemenes oileus (Westwood, 1859) , which is likely a Javan endemic species, and Hennemann (1998: 125) erronously listed gravidus as a synonym of the Wallacean P. coronatus (Haan, 1842) . Here gravidus is re-established as a valid species because there are fundamental morphological differences that separate P. gravidus from all other known Wallacean members of Pylaemenes (rev. stat.).

The specimens at hand for examination from the first author’s collection represent the first record of P. gravidus from the island of Morotai whereas the specimens from the collection of NMEG are the first records from the islands of Bacan and Ternate. These specimens show the species to be widely distributed throughout Maluku Utara Province.

Comparison of the holotype ♀ nymph of Datames aequalis Rehn, 1904 from the island of Obi ( Fig. 2 G-H) with the immatures at hand from the islands of Bacan and Ternate in the collection of NMEG leave no doubt they are the same species because morphologically they agree in every aspect. Thus, Rehn’s species is here synonymised with P. gravidus (n. syn.) and shows this species to be distributed throughout almost the whole of the northern Maluku islands.

The specimens erroneously listed as “ Datames oileus ” from the Talaud Islands by Günther (1934: 76) could not be traced for the present study, hence their true identity remains unknown. They might be P.gravidus or a variety of P.moluccanus (Redtenbacher, 1906) but also could represent an undescribed species that is closely allied to either species.

Measurements of the two Morotaian ♀ in the first authors collection [mm]:

- Body 48.5 -49.5,

- Pronotum 3.9- 4.0,

- Mesonotum 9.9- 10.0,

- Metanotum 4.2- 4.4,

- Median segment 1.8-1.9,

- Profemora 9.2-9.3,

- Mesofemora 6.7-6.8,

- Metafemora 7.7-8.0,

- Protibiae 7.0- 7.2,

- Mesotibiae 7.0- 7.2,

- Metatibiae 7.8- 8.0,

- Antennae 19.0- 19.3.

Bates (1865: 343) cited a body length of 50.3 mm for the holotype in OUMNH.

Distribution.

Halmahera. – “Gilolo” [OUMNH]; 7-10km S of Jailolo, 200 m [NMEG].

Morotai. – Daeo Majiko village [coll. FH]; Daruba [coll. FH].

Bacan. – 10km E Labuha, 120 m [NMEG].

Ternate. – Laguna Lake [ NMEG].

Obi Island [ ANSP].

A. ♀ dorsal view [FH, No. 0828-30]. B. ♂ dorsal view [FH, No. 0828-44].