Carmona et al. (2014) studied the genus Spurilla Bergh, 1864 in depth, and concluded “that coloration is one of the main diagnostic traits for the five species” of the genus, “although some display substantial colour pattern variation”. These authors also established the distribution of the western Atlantic species: S. dupontae and Spurilla sargassicola Bergh, 1871 inhabit the Bahamas, and Spurilla braziliana MacFarland, 1909, the only representative of Spurilla in the Caribbean.
Carmona et al. (2014) observed "an intriguing combination of widespread species and endemics with restricted ranges" for the members of the genus Spurilla, while some recent papers on heterobranch sea slugs published by Ornelas-Gatdula et al. (2011), Ornelas-Gatdula and Valdés (2012), Carmona et al. (2013), proved the presence of some new cryptic species in the Bahamas not known in the Caribbean subprovince. In this context, it seemed logical to assume that S. dupontae was endemic to the Bahamas, as Carmona et al. (2014: 150) did. But the specimen of S. dupontae found in Martinique matches exactly on the original description of the species, and it is easy to distinguish from S. braziliana and S. sargassicola by the conspicuous reticulate pattern covering the body, and specially the rhinophores.
Since its original description, there has not been any records to S. dupontae in the Caribbean or anywhere else, but S. sargassicola, which shows certain similarities with S. dupontae, has been cited by Caballer et al. (2015) in Venezuela. This specimen from the southern end of the Caribbean, was collected on Caulerpa spp. and the illustration provided by Caballer et al. (2015: 5 E) shows an animal with a reticulate pattern that seem to include the rhinophores, thus, this record could be, indeed, attributed to S. dupontae. On the other hand, the Guadeloupe Archipelago is very close to Martinique, and nearer to the Bahamas. However, S. dupontae has not been captured there, not even after the intensive expeditions performed by the Muséum national d’Histoire naturelle (Paris) in 2012, which permitted a wide study of the sea slug fauna from the Archipelago (Ortea et al. 2012; Ortea et al. 2013; Caballer and Ortea 2014; Caballer and Ortea 2015) and the capture its congener S. braziliana (as S. neapolitana).
It has been stated that the Bahamas and the Turks and Caicos Islands are a special region in the western Atlantic, largely isolated from the Caribbean, except for minor exchange from the north coast of Cuba and Haiti (Cowen et al. 2006). The presence of S. dupontae in the Caribbean subprovince (even when scarce), implies that planktotrophy is the most probable way of development for this species, and suggests that there may be more gene flow between the Bahamas and the Lesser Antilles than that predicted by the model owed to Galindo et al. (2006).
In synthesis, further collections of S. dupontae are necessary to learn its real distribution in the Caribbean Province and to determine if its presence in Martinique is incidental or if the species is really established in the Island.