Rhynchodemus sylvaticus (Leidy, 1851)

Luna, Manuel De & Boll, Piter Kehoma, 2023, An annotated checklist of terrestrial flatworms (Platyhelminthes: Tricladida: Geoplanidae) from Mexico, with new records of invasive species from a citizen science platform and a new nomen dubium, Zootaxa 5297 (4), pp. 518-532 : 528-529

Rhynchodemus sylvaticus (Leidy, 1851)

Figs. 24–26 .

External diagnosis ( Ball & Reynoldson 1981; Ball & Sluys 1990). Anterior region flattened and narrowed into a proboscis-like appearance. Usually pale or brownish gray. Along the dorsal surface there are two dark longitudinal stripes which are often united with a dark saddle in the pharyngeal region; rarely, mostly in dark specimens, the stripes are inconspicuous. The ventral surface is pale. There are two large eyes situated distantly from the anterior tip. Very small, up to 15 mm, but usually smaller.

The absence of a head plate differentiates it from both species of Bipalium and the paired eyes differ from all recorded Caenoplanini as well as Geoplana multipunctata . This species has a narrow anterior region, unlike Diporodemus yucatani which has a rounded one. Rhynchodemus sylvaticus is much smaller than both Dolichoplana and only has two dorsal stripes.

Remarks. This species is found in the Holarctic region ( Ball & Reynoldson 1981; Ball & Sluys 1990) and is considered European ( Álvarez-Presas et al. 2014)

iNaturalist Records. MEXICO: JALISCO: One specimen observed 16 October 2019; 20.5487, -104.0392; uploaded by chriss666 (#34503888) .

Figures

FIGURES 17–25. Illustrations of invasive species of Rhynchodemini found in Mexico: (17) dorsal aspect of Dolichoplana carvalhoi with a dorsal pattern of five stripes; (18) dorsal aspect of D. carvalhoi and Dolichoplana striata with a dorsal pattern of six stripes; (19) detail of the dorsal aspect with six stripes; (20) detail of the dorsal aspect with a pattern of four stripes found in some specimens of D. striata; (21) detail of the dorsal aspect with five stripes; (22) detail of the ventral aspect of D. striata and D. carvalhoi with six dorsal stripes; (23) detail of the ventral aspect of D. carvalhoi with five dorsal stripes; dorsal (24) and ventral (25) aspect of Rhynchodemus sylvaticus. Scale bars: 5 mm.

FIGURE 26. Map of Mexico pointing the iNaturalist records of the invasive terrestrial flatworms, excluding hammerhead flatworms (for those see de Luna et al. 2022): Caenoplana coerulea (blue circle), Dolichoplana carvalhoi (red hexagon), Dolichoplana striata (yellow hexagons), Endevouria septemlineata (orange squares), Parakontikia ventrolineata (green triangles), and Rhynchodemus sylvaticus (pink hexagon).