- Molecular and morphological systematics of Elysia Risso, 1818 (Heterobranchia: Sacoglossa) from the Caribbean region
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- Krug, Patrick J., Vendetti, Jann E., Valdés, Ángel (2016): Molecular and morphological systematics of Elysia Risso, 1818 (Heterobranchia: Sacoglossa) from the Caribbean region. Zootaxa 4148 (1): 1-137, DOI: http://doi.org/10.11646/zootaxa.4148.1.1
- Elysia christinae
Host ecology. About 15 specimens of E. christinae n. sp. were recovered from a sample of the udotacean alga Rhipilia tomentosa. The alga was growing at ~ 6 m depth, in a sandy patch within a large seagrass bed. Slugs were mostly juveniles <5 mm long. Slugs were maintained in aquaria on R. tomentosa and observed for three months. All specimens preferentially associated with R. tomentosa and not other related algae growing in the aquaria (Udotea, Caulerpa, Halimeda). Slugs were observed feeding only on R. tomentosa in the laboratory. White spots on a green background color make live animals highly cryptic on their host alga, due to the numerous white calcareous structures made by fouling organisms on the surface of Rhipilia (Fig. 64 A – B). Phylogenetic relationships. Elysia christinae n. sp. belongs to subclade 1, a group of Caribbean species. Within this lineage, no sister species was recovered with significant support. Subclade 1 includes lineages that have radiated onto multiple genera of udotacean algae, and are physically associated with their hosts — Penicillus (E. papillosa, E. taino n. sp.), Udotea (E. zuleicae, E. buonoi n. sp.), Rhipilia (E. christinae), and Halimeda (E. patina). These lineages thus remain ecologically partitioned at a fine spatial grain due to host specificity, and being co-distributed but differentiated by host use, may represent an adaptive radiation driven by ecological speciation.
Etymology. Named in honor and fondest memory of Christine Marie Donnelly Lee and her daughter Christine Marie Lee, loving grandmother and aunt of PJK.
Type material. Bimini, Bahamas, July 2010, (Holotype LACM 3308, Paratype LACM 3309 [2 in lot]), collected by PJK. Type locality. Bimimi, Bahamas Material examined. Bimini, Bahamas, July 2010, 10 specimens, (Holotype LACM 3308, Paratype LACM 3309 [2 in lot], isolate Echr _ 10 Bim 04 - 10). Live animal. Slugs resting on the algae held their parapodia open and flattened against the algal surface (Fig. 64 A – B). When crawling, slugs typically elevated the parapodia along the anterior two-thirds of the body length, assuming a more typical slug-like shape, but the posterior third of the parapodia remained open and flattened, creating a widened, rounded end of the body (Fig. 64 C – D). On crawling slugs, parapodial edges undulate. The head can be used to grip the substrate, and the front two-thirds of the body can rear up like a snake.
- Elysia christinae