Pseudobiceros evelinae ( Marcus, 1950 )

Bahia, Juliana, Padula, Vinicius & Delgado, Marlon, 2012, Five new records and morphological data of polyclad species (Platyhelminthes: Turbellaria) from Rio Grande do Norte, Northeastern Brazil, Zootaxa 3170, pp. 31-44 : 37-38

Pseudobiceros evelinae ( Marcus, 1950)

( Fig. 4 )

Material examined and locality. One mature specimen (16 mm x 15 mm) as sagittal sections of reproductive structures (17 slides, MNRJ-PLAT 11). One juvenile specimen (6 mm x 5 mm) preserved in ethanol 70%, collected 11 March 2009 (MNRJ-PLAT 12).

Seven specimens (13 mm x 6 mm, 12 mm x 7 mm, 11 mm x 10 mm, 12 mm x 12 mm, 13 mm x 9 mm, 8 mm x 6 mm and 6 mm x 4 mm) preserved in ethanol 70%, collected 9 March 2009 (MNRJ-PLAT 13). All specimens collected at Brazil, RN, Extremoz, Praia de Santa Rita, 0 5o 41’44’’S; 35o11’39’’W, intertidal, under rocks.

Distribution. Originally described from Forte de Itaipú, Santos, São Paulo State, Brazil. Also collected in Cabo Frio, Rio de Janeiro State, Southeastern Brazil (Bahia, unpublished data). Specimens were collected under rocks, associated with ascidians. Rio Grande do Norte represent the northernmost report of this species to date.

Diagnosis. Elongated body with ruffled margin; background color wine red with three marginal bands; inner black, middle orange and thinner outer black band. Tentacular eyespots arranged in four dorsal and four ventral clusters. Doubled male reproductive structures.

Description. Color: Background wine red, darker toward the margins. Three marginal bands present. Internal black band broad, middle orange band surrounded by a black thinner band ( Fig. 4 A). The inner black band is visible mostly on bright backgrounds, when in dark background or in the field this band appears merged with the dorsal coloration as if it was a denser pigmentation near the margins. All bands interrupted in the zone between tentacles. The black outer band remains conserved after fixation. Cerebral area unpigmented. Ventral color pattern same as dorsally in live worms. After fixation it turns creamy.

Form: Elongated with rounded ends ( Fig. 4 A). Highly ruffled margins ( Fig. 4 B). After fixation the body distends and becomes rounded.

Tentacles: Margin folds turned backwards that reaches 1.2 mm. Tentacular tips whitish ( Fig. 4 A).

Eyespots: Each tentacle bears four eyespots clusters, two dorsal and two ventral. Two are proximal and two distal. Ventro-distal groups bear 50 eyespots and ventro-proximal clusters around 35 eyespots. Dorsal groups could not be counted due to tentacle folding and coloration. Cerebral eyespot cluster in horse-shoe shape and bearing 13 – 25 eyespots.

Digestive system: Pharynx 4 mm long, numerously but tenuously folded. Mouth opens at 5 mm from the anterior margin. Pharyngeal folds filled with eosinophilous granules that might be remains of the specimen food (synascidians).

Epidermis and body wall: Epidermis short ciliated (0.037 mm) with a strong basal membrane. Rhabdites present and abundant both dorsally and ventrally. Thin muscular layers 0.014 mm thick, consisting of longitudinal, circular and diagonal fibers, respectivelly. Loose parenchyma. Sucker voluminous, 1.2 mm distant from the female gonopore and 0.3 mm large. Subcutaneous pigmentation can be seen in histological sections. Cutaneous glands numerous on the dorsal surface and also present ventrally.

Gonopores: Two male and one female gonopores present. Male gonopores 0.2 mm large and 7.4 mm distant from the anterior margin, positioned on each side of the median line of the body ( Fig. 4 C). Female gonopore 0.8 mm distant from the male gonopore, located in the median body line and 0.15 mm large ( Fig. 4 C).

Male reproductive system: Ventrally disposed testes. Male system doubled with corresponding vesicles, stylet (0.09 mm), and penis papilla. Penis (0.24 mm) and male atrium directed backwards ( Fig. 4 D). Male atrium 0.24 mm deep. Large seminal vesicle (0.54 mm) reaches twice the copulatory structure size. Seminal ducts are repeatedly expanded forming seminal accessory vesicles that reach 0.61 x 0.44 mm. The main seminal vesicle joins the penis papilla posteriorly through an ejaculatory duct. Prostatic vesicle anteriorly disposed ( Fig. 4 D) and 0.26 x 0.13 mm large.

Female reproductive system: Vagina short, 0.13 mm long. Female atrium 0.11 mm deep. Cement pouches (0.04 mm) surrounded by dense masses of cement glands ( Fig. 4 E). Uteri occur dorsally to testes and ventrally to intestine. Uterine duct curved backwards and joining the vagina right under a pharyngeal fold.

Taxonomic remarks. Pseudoceros species were acknowledged as remarkably homogeneous internally ( Newman & Cannon 1996). After the proposition of the genus Pseudobiceros ( Faubel 1984) , Pseudoceros species that presented two male gonopores were relocated in the new genus. Pseudoceros was restricted to species with only one male system present. Faubel (1984) therefore recognized the species described by Marcus as Pseudobiceros evelinae . Our specimens fit the characteristics reported on the original description (tentacular eyespots disposal, color pattern and reproductive structures). There are 22 Pseudobiceros species and nine of them present the “even color & distinct marginal bands” color pattern, P. evelinae being the only species with red as even color known up to date ( Newman & Cannon 1997).

Figures

FIGURE 4. Pseudobiceros evelinae. A – B (MNRJ-PLAT 13). A— in vivo, dorsal view; B— in vivo, ventral view. C—E (MNRJ-PLAT 11). C— ventral structures; D— sagittal section with indication of male reproductive structures; E— sagittal section with indication of female reproductive structures. cg: cement gland; cp: cement pouches; ed: ejaculatory duct; fg: female gonopore; it: main intestine; ma: male atrium; mg: male gonopore; ph: pharynx; pt: pseudotentacles; pv: prostatic vesicle; st: stylet; su: sucker; sv: seminal vesicle; ut: uteri; vs: vas deferens.