Elysia deborahae Ortea, Espinosa & Moro in Ortea, Caballer Moro & Espinosa, 2005

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), pp. 1-137 : 92-93

Elysia deborahae Ortea, Espinosa & Moro in Ortea, Caballer Moro & Espinosa, 2005

(Not figured)

Elysia patina [non Ev. Marcus 1980: 72–73, figs. 23–24, 36, 41–43, 57] — Ev. Marcus 1980: figs. 59, 60).

Elysia deborahae Ortea, Espinosa & Moro in Ortea, Caballer Moro & Espinosa 2005: 509 –512, fig. 5, pl. 1D. Checholysia deborahae (Ortea, Espinosa & Moro, 2005) — Ortea et al. 2005: 512; Espinosa et al. 2005: 56.

Type material. Elysia deborahae— holotype at IOH (no catalogue number provided).

Material examined. No specimens available.

Live animal. According to Ortea et al. (2005) the foot of the live animals secretes an adhesive mucus that allows the animals to attach themselves firmly to the substrate. When disturbed the animals can swim by slowly flapping the parapodia.

External anatomy. Summarized from Ortea et al. (2005). Body orange-brown with microscopic blue dots and small yellow tubercles. Parapodia with straight edge, pigmented with brown along its entire length or in segments. In live animal parapodia enter in contact with each other in center of body, becoming separate towards posterior and anterior ends. In area of contact there is an olive-oil elongate patch with a bright blue spot on its anterior half and snow white pigment on its posterior half. Sides of the body with 2–3 snow white conical papillae with blue pigment around their bases. Head white or orange with blue spots and two orange lines running from eyes to parapodia and several ramified green lines. Foot sole translucent orange with viscera visible through skin. Rhinophores elongate, about ¼ of total length of animal, reddish-brown with small white papillae. Pericardium globose anteriorly and elongate posteriorly extending backward beyond the center of body, pigmented with orange and white. Dorsal vessels orange, arranged in two main anterior branches that are ramified from their proximal end and two main posterior branches, which ramified closer to their distal end.

Internal anatomy. Summarized from Ortea et al. (2005). Radula with 15 teeth, 7 in ascending limb (plus one in development) and 7 in descending limb. Leading tooth elongate with a sharp cusp and lacking denticles. Base of tooth thickened, wide and elongate, about ½ total tooth length. Ascus with two teeth. Penis pyriform with a distal stylet, 55 µm long.

Reproduction and development. No data available.

Host ecology. Ortea et al. (2005) reported collecting live animals on Halimeda and Lobophora but there is no direct evidence for the actual diet of this species.

Phylogenetic relationships. No data available.

Range. Cuba (Espinosa et al. 2005)

Remarks. Confoundingly, Ortea, Caballer, Moro & Espinosa in Ortea et al. (2005) described E. deborahae but asserted that this species was synonymous with E. patina , referring to figures of both the type specimen (Ev. Marcus 1980: figs. 23–24) as well as a second specimen not included in the type series of E. patina (Ev. Marcus 1980: figs. 59–60). Ortea et al. (2005) inferred that Ev. Marcus (1980) had two species mixed together in her description of E. patina , but Ev. Marcus (1980) clearly differentiated the non-type specimen from the Bahamas (figs. 59–60) as likely representing a distinct species. If E. deborahae is synonymous with the type specimen of E. patina as figured by Ev. Marcus (1980) in figs. 23–24, then it is a junior synonym. If E. deborahae is instead only synonymous with the material figured by Marcus (1980) in figs. 59–60, then it could be a valid species, although the basis for this claim is uncertain as the dorsal vessel networks are not comparable.

Elysia deborahae closely resembles E. zuleicae , and while Ortea et al. (2005) presented a series of supposedly distinguishing features that separate E. deborahae , most do not appear to be diagnostic. A major supposed difference between E. deborahae and E. zuleicae was that a penial stylet was present in E. deborahae but reported to be absent from E. zuleicae ; however, a stylet is normally present in E. zuleicae , so this is not a distinguishing feature. Ortea et al. (2005) described E. deborahae as having a lighter coloration, but specimens of E. zuleicae show tremendous intra-specific variation in external coloration ( Fig. 51 ); some are very pale, making color a potentially unreliable character. Similarly, the parapodial margin was described as smooth in E. deborahae versus papillose in E. zuleicae , but parapodial morphology is highly variable in E. zuleicae .

The radular tooth of E. deborahae was described and figured as smooth by Ortea et al. (2005), and curved like that of E. zuleicae with a “ Halimeda spur” morphology. Ortea et al. (2005) proposed two differences between the radulae of E. zuleicae and E. deborahae : (1) in E. zuleicae , the maximum height of the curved blade of radular teeth was attained behind the anterior edge of the base of the tooth, whereas in E. deborahae , the maximum height attained after the edge of the base; and (2) more teeth were present in the descending limb of the radula in E. zuleicae . However, the number of teeth in the descending limb depends on age, and the specimens of E. deborahae examined may have been juveniles (3–4 mm). Our SEMs reveal that the maximum tooth height in E. zuleicae is attained after the front of the base of the tooth, as described for E. deborahae , and not before the front edge as was reported for E. zuleicae ; therefore, no radular character distinguishes E. deborahae .

An anatomical character that was also proposed to differentiate E. deborahae from E. zuleicae was the absence of an extended tail in E. deborahae . In E. zuleicae , a narrow, pointed tail usually extends beyond the point where the posterior edge of the parapodia fuse with the dorsal surface of the body. However, half the specimens of E. zuleicae we examined from the U.S. Virgin Islands lacked a tail, yet were genetically indistinguishable from the tailed specimens; indeed, as our figured specimens show ( Fig. 51 ), there is great intra-specific variability in tail size, color and even presence in E. zuleicae . It is possible that there is a species similar to E. zuleicae with smooth, curved radular teeth and no tail, but we have sampled no such species. We describe a species (see below) that is sister to E. zuleicae , lacks a tail, but that has serrated, curved teeth, making it distinct from E. deborahae .

Figures

FIGURE 51. Elysia zuleicae, external morphology and egg masses from Discovery Bay, Jamaica (A; March 2006); Little San Salvador, Bahamas (B – D, F, H; July 2007); or Bocas del Toro, Panama (E, G; December 2004). All measurements give body length of specimens. A, Specimen (8 mm) with light-colored rhinophores, parapodial margin and tail. B, Side view of specimen (12 mm) with dark maroon rhinophores, marginal bands of purple and brown on dark green parapodia, and thin, dark-colored tail. C, Top view of same specimen, showing parapodial margin, short renopericardial extension, and head. D, Ventral view of foot. E, Dorsal view with parapodia open, showing renopericardial complex, dorsal vessel network, and white gametic vesicles. F, Light-colored specimen (8 mm) with black speckling inside parapodia and on dorsal vessels. G, Light-colored juvenile (3 mm) with parapodia held flat against the substrate. H, Dark-colored juvenile (3 mm) with black marginal line. I, Planktotrophic egg mass laid by specimen from Jamaica, showing white ECY ribbon intercalated among early-stage embryos. Field of view = 2.1 mm. J, Lecithotrophic egg mass laid by specimen from Plana Cays, Bahamas, showing thick white ECY ribbon on upper inside face of egg mass, and encapsulated veliger larvae. Field of view = 6.8 mm. K, Lecithotrophic egg mass laid by specimen from Sweetings Cay, Bahamas, showing remnants of white ECY ribbon intercalated among encapsulated late-stage veliger larvae, close to the point of hatching. Field of view = 2.1 mm.