Ptenidium

Darby, Michael, 2014, Studies of Madagascan Ptiliidae (Coleoptera) 2: The genus Ptenidium including three new species, Zootaxa 3793 (3), pp. 350-360 : 352

Key to the Ptenidium of Madagascar

(omits P. planum and P. improvisum )

1. Sides of pronotum with a medial seta-bearing fovea and marginal sinuation (Figs. 5,6).............................. 2

- Sides of pronotum without a distinct medial fovea and sinuation (Fig. 4).................................. P. azafady

2. Smaller species 0.75–0.80 mm ........................................................................... 3

- Larger species 0.87–1.07 mm ............................................................................4

3. Sides of pronotum more evenly rounded with only an indistinct medial sinuation, darker, smaller species +/- 0.75 mm .................................................................................................. P. cognatum

- Sides of pronotum less evenly rounded more distinctly foveate and sinuate (Fig. 5), slightly lighter, larger species 0.77–0.80 mm ......................................................................................... P. lambdai

4. Base of pronotum narrower, the strongly rounded sides forming a right angle with the anterior margin of the elytra, medial fovea and sinuation indistinct..................................................................... P. vadoni

- Pronotum base wider, sides forming an obtuse angle with the elytra, much less strongly rounded and with a distinct medial fovea and sinuation (Fig. 6)....................................................................... P. tanalai