Eurylepta aurantiaca Heath & Mc Gregor 1912

Bahia, Juliana, Padula, Vinicius, Lavrado, Helena Passeri & Quiroga, Sigmer, 2014, Taxonomy of Cotylea (Platyhelminthes: Polycladida) from Cabo Frio, southeastern Brazil, with the description of a new species, Zootaxa 3873 (5), pp. 495-525 : 520-521

Eurylepta aurantiaca Heath & Mc Gregor 1912

( Fig. 19 )

Material examined. One specimen (12 x 4 mm) as sagittal sections of reproductive structures (MNRJ-PLAT 76, 11 slides). Collected 20.04.2008 at Praia das Conchas, Cabo Frio, Brazil (22°52'33.05"S, 41°58'39.27"W).

Distribution. Described from Monterey Bay, California ( Heath & McGregor 1912) and reported from Washington State, USA ( Hyman 1955a) and from the Caribbean coast of Colombia ( Quiroga et al. 2004b). This is the first record from Brazil.

Diagnosis. Translucent body, with red longitudinal line, interrupted several times; small white dots disposed in the dorsal surface and in a transversal line at the posterior end of the body. Two long uterine vesicles; main intestine with seven or eight branches at each side.

Description. Color: Translucent body, color is due to intestine content. Our specimen was pinkish orange. White spots present dorsally, at the middle dorsal region after the cerebral eyespots and as a transversal line at 4.5 mm from anterior margin. Median line reddish, interrupted several times ( Fig. 19 ). Reddish dots also occur dorsally at each side of the median line. Whitish tentacles.

Form: Oval, elongated.

Pseudotentacles: Tentacles pointed and thin measuring 0.6 mm.

Eyespots: Tentacular eyespot groups located dorsally at tentacle extremities (8–12 eyespots) and between tentacles (13–15 eyespots); ventrally at tentacle extremities (17–25 eyespots). Cerebral eyespots at 0.9 mm from the anterior margin, in two elongated groups (0.4 x 0.2 mm) and very near one of the other, each with about 15 eyespots.

Digestive system: Tubular pharynx measures 1.4 mm. Main intestine with eight branches, without anastomoses, occupying 53% of the body.

Epidermis and body wall: Dorsal epidermis (40 µm) taller than ventral epidermis (20 µm). Basal membrane well developed, with eosinophilic coloration and 9 µm thickness. Thin body wall, with circular muscular layer externally and diagonal muscular layer internally. Muscular layers with 0.010 µm thickness dorsally and 0.020 µm ventrally. Sucker at 3.5 mm from the anterior margin, measures 0.2 mm.

Gonopores: Male gonopore at 2.4 mm from the anterior margin, measures 0.2 mm. Female gonopore located right after, measures 0.22 mm. Both at the median line of the body.

Male reproductive system: Our specimen was immature and it was not possible to observe prostatic and seminal vesicle, penis, and other male structures. Testicles also could not be identified in the histological sections, which corroborates the immaturity of our specimen.

Female reproductive system: Female apparatus of our specimen also immature, cement glands could not be observed and nor a well-defined vagina.

Taxonomic remarks. Our specimen is in accordance with the original description ( Heath & Mc Gregor 1912), despite small variations in color. This does not represent a strong character in Euryleptidae , especially in translucent species that are colored by the food content present in the intestine. However, the general coloration pattern, with the presence of a median line and small white dots dorsally, is the same as originally described ( Heath & McGregor 1912, pg: 481).

Three Eurylepta species are known from Brazil; all present differences in coloration pattern, eyespot group arrangement and number of intestine branches. Differences between our specimen and Eurylepta piscatoria ( Marcus 1947) are the coloration pattern, body form and both cerebral and tentacular eyespot group arrangement ( Marcus 1947, pg: 136 and 205). Eurylepta neptis Dubois-Reymond Marcus 1955 and E. turma Marcus 1952 present lower number of main intestine branches and cerebral eyespot group wider and shorter ( Marcus 1952, pg: 94 and 183; Dubois-Reymond Marcus 1955, pg: 43). Another species from this genus with similar coloration pattern and Western Atlantic distribution is E. maculosa Verrill 1892 . This species differs from our specimen in the cerebral and tentacular eyespot arrangement ( Hyman 1939b, pg: 149; Hyman 1952, pg: 198). Eurylepta multicelis ( Hyman 1955b) differs from our specimen also in eyespot arrangement and in the presence of peripheral glands.

Figures

FIGURE 19. Eurylepta aurantiaca (MNRJ-PLAT 76). A. in vivo, dorsal view; B. ventral view; C. detail from the anterior region showing eyespots and tentacle bumps; D and E. sagittal sections of the body. ce: cerebral eyespots; ep: epidermis; gp: gonopores; it: main intestine; ml: muscular layer; ph: pharynx; su: sucker; te: tentacular eyespots; tc: tentacles.