Platevindex

Goulding, Tricia C., Bourke, Adam J., Comendador, Joseph, Khalil, Munawar, Quang, Ngo Xuan, Tan, Shau Hwai, Tan, Siong Kiat & Dayrat, Benoît, 2021, Systematic revision of Platevindex Baker, 1938 (Gastropoda: Euthyneura: Onchidiidae), European Journal of Taxonomy 737 (1), pp. 1-133 : 124-125

A key is provided to help identify the nine species of Platevindex . Because species cannot always be distinguished externally, the key also includes internal characters.

1. Dorsal eyes absent, penial hooks absent, intestinal loops of type III..........................................2

– Dorsal eyes present, penial hooks present (in mature specimens), intestinal loops of type I or II, but never of type III...........................................................................................................................3

2. Dorsal surface bears large, thorny papillae ...................................................... P. latus ( Plate, 1893)

– Dorsal surface bears only small papillae ................................................ P. amboinae ( Plate, 1893)

3. Hyponotum yellow with dark spots, foot orange or black, dorsal surface bears low longitudinal ridges, dorsal eyes can be very close (<2 mm) to the notum edge........................4

– Hyponotum variable (white, light to dark grey, light blue to dark blue) but not marked by distinct dark spots, foot light to bright yellow (exceptionally dark blue-grey), dorsal surface without small longitudinal ridges, dorsal eyes are not very close (<2 mm) to the notum edge.........5

4. Foot bright or dark orange ........................................................................... P. martensi ( Plate, 1893)

– Foot black ................................................................................. P. aptei Goulding & Dayrat sp. nov.

5. Notum bears distinctly-raised papillae (with or without eyes), slug frequently semi-hemispherical (especially when disturbed)...............................................................................................................6

– Notum granular, with papillae with dorsal eyes but no distinctly-raised, prominent papillae, slugs normally remain flattened (even when disturbed)............................................................................7

6. No bright yellow longitudinal areas on dorsal notum, intestinal loops of types I or II with a transitional loop oriented between 3 and 8 o’clock, retractor muscle of penis inserts near heart ......... ....................................................................................................................... P. luteus ( Semper, 1880)

– Bright yellow longitudinal areas present on dorsal notum, intestinal loops of type I with a transitional loop oriented between 1 and 2 o’clock, retractor muscle of penis inserts near heart or at posterior end of visceral cavity ................................................... P. applanatus ( Simroth, 1920)

7. Distal portion of oviduct (distal to spermatheca) shorter than proximal portion (from female gland mass to spermatheca) ............................................................................... P. burnupi ( Collinge, 1902)

– Distal portion of oviduct (distal to spermatheca) much longer than proximal portion (from female gland mass to spermatheca)...............................................................................................................8

8. Retractor muscle of penis inserts near heart, distal region of penis (with hooks) less than 1.5 mm long, deferent duct attached to oviduct (in posterior part of reproductive system) and almost straight ..................................................................................................... P. tigrinus ( Stoliczka, 1869)

– Retractor muscle of penis inserts near posterior end of visceral cavity, distal region of penis (with hooks) more than 2 mm long, deferent duct attached to oviduct (in posterior part of reproductive system) and highly coiled ...................................................................... P. coriaceus ( Semper, 1880)