Phyllium

Cumming, Royce T. & Teemsma, Sierra N., 2018, A new species of Phyllium (Phyllium) Illiger (Phasmida: Phylliidae) from Yap Island, Micronesia, representing a range expansion for the family, Insecta Mundi 650, pp. 1-9 : 4-5

Key to females of known species of the celebicum species group

Adapted from the Hennemann et al. (2009) key. Distributional data cited in this key obtained from Hennemann et al. (2009), Cumming et al. (2017), Thanasinchayakul (2006), and Seow-Choen (2017).

Females of Ph. (Ph.) parum Liu, 1993 and Ph. (Ph.) yunnanense Liu, 1993 are currently unknown.

Morphologically the holotype of Ph. (Ph.) rayongii Thanasinchayakul, 2006 is indistinguishable from Ph. (Ph.) westwoodii Wood-Mason, 1875 and therefore cannot be separated in a dichotomous key. The authors question the validity of Ph. (Ph.) rayongii and suspect it is simply a synonym of Ph. (Ph.) westwoodii based on the following reasoning. Phyllium (Ph.) westwoodii is a morphologically variable species, especially in regards to abdominal shape, and from examination of photos of the holotype Ph. (Ph.) rayongii ( Brock et al. 2018) , the specimen clearly falls within the intraspecies variation of Ph. (Ph.) westwoodii discussed at length by Hennemann et al. (2009). Thanasinchayakul (2006) based their morphological key and most of their discussion on species solely on abdominal shape, not on other stable diagnostic features with more differentiation ability. such as the profemora, thorax, or antennae. We expect that if Thanasinchayakul (2006) examined these stable features in a series of specimens, they would likely have not described Ph. (Ph.) rayongii as a separate species.

1. Metatibia with exterior lobe....................................................... 2

— Metatibia without exterior lobe.................................................... 3

2(1). Small species (body length <80mm); abdominal segment VII gradually narrowing; exterior lobes of meso- and metatibiae distinct, expanding over almost entire length of tibia; Sri Lanka.................................... Ph. (Ph.) athanysus Westwood, 1859

— Large species (body length 106.5mm); abdominal segment VII roundly angulate; all tibiae with a small, rounded lobe near apex of tibia; SW-China (Tibet). Ph. (Ph.) tibetense Liu, 1993

3(1). Mesopleurae distinctly diverging throughout the entire length.......................... 4

— Mesopleurae narrow for the anterior one third to one half, then remainder prominently diverging................................................................... 7

4(3). Abdominal segment VI with parallel or slightly subparallel lateral margins giving the abdomen a boxy appearance........................................................... 5

— Abdominal segment VI with converging lateral margins giving the abdomen a spade shaped appearance; S. China (Guangxi Prov.).................... Ph. (Ph.) rarum Liu, 1993

5(4). Protibiae interior lobe reaching end to end in a smooth triangle that is evenly distributed on the distal and proximal ends or only slightly shifted towards the distal end................ 6

— Protibiae interior lobe unevenly distributed, almost entirely on the proximal half, with the distal half greatly reduced; Micronesia, Yap Is....................................................................... Ph. (Ph.) yapicum Cumming and Teemsma n. sp.

6(5). Abdominal segment VII lateral margin with distinct lobe; angle of profemora exterior lobe approximately 90 degrees; Philippines (Luzon Is., Batan Is., Marinduque Is., Catanduanes Is.).................................. Ph. (Ph.) ericoriai Hennemann et al., 2009

— Abdominal segment VII lateral margin with indistinct lobe and converging posteriorly; angle of profemora exterior lobe obtuse; Philippines (Northern Luzon Is.) Ph. (Ph.) bonifacioi Lit and Eusebio, 2014

7(3). Angle of exterior lobe of profemora> 90°, angle rounded............................... 8

— Exterior lobe of profemora acutely angled (<90°), angle distinct; Indonesia (Sulawesi)............................................ Ph. (Ph.) celebicum de Haan, 1842

8(7). Alae about half of the length of the tegmina; Singapore.......................................................................... Ph. (Ph.) chrisangi Seow-Choen, 2017

— Alae greater than two thirds the length of tegmina; Andamans, Myanmar, Thailand, Laos, Kamputchea, Vietnam and S-China.......... Ph. (Ph.) westwoodii Wood-Mason 1875 / Thailand: Ph. (Ph.) rayongii Thanasinchayakul, 2006