Pseudobiceros uniarborensis Newman and Cannon, 1994

Maghsoudlou, Abdolvahab & Rahimian, Hassan, 2014, Contribution to the knowledge of cotylean flatworms (Turbellaria, Polycladida) from Iranian coasts: Introducing a new species, with remarks on new records, Zootaxa 3860 (4), pp. 325-342 : 332-333

Pseudobiceros uniarborensis Newman and Cannon, 1994

( Figure. 4 )

Type locality. Great Barrier Reef- Australia

Other localities. Western Australia, Hawaii, Indonesia, Mauritius, Micronesia, Papua New Guinea, Red Sea, Philippines ( Newman & Cannon 2005)

Location in Iran. Sampling locality composed of rocky substrate, with numerous small and large intertidal pools covered with red and brown algae, ascidians and sponges. Specimens sparsely distributed, collected from under rocks, associated with didemnid ascidians ( Fig. 10 B), were observed only in the coasts of the Gulf of Oman ( Fig. 1 station 36, and Table. 1).

Material examined. Four live specimens were examined in vitro ( Fig. 4 ). Unfortunately all of them were lost during fixation, so histological serial sections were not prepared. In Pseudobiceros the dorsal color pattern is taxonomically more important than the details of the reproductive anatomy ( Newman & Cannon 1997). Consequently the identification was based on this trait only.

Description. Living animals with delicate body, highly ruffled margin, dark brown; dorsal surface with three narrow marginal bands: inner band bright orange, followed by a wide clear band, and a whitish grey rim. The ventral side is brown with a white marginal band. Size of the living specimens, at rest, 3 cm × 1 cm (in smallest specimen) to 5.5 cm × 1.6 cm (in largest specimen) ( Fig. 4 ). The pseudotentacles are ear-like, and are held erect in live animals, 2.6 mm long, dark brown without marginal bands, with white tip, and a white-grey triangle extending to the cerebral eyespots ( Fig. 4 ); the cerebral cluster made up of about 63 eyespots; the pharynx is typical of the genus, with simple folds. In ventral view the two male gonopores are situated close to one another.

Remarks. Prior to 1984, polyclad taxonomists believed that the majority of conspicuous and colorful pseudocerotid flatworms belonged to the genus Pseudoceros Lang, 1884 . Faubel (1984a) erected the new genus Pseudobiceros and transferred all Pseudoceros species with double male systems into the new genus. Since then, Pseudobiceros has been further validated by traits such as pharynx type, arrangement of cerebral eyes, ruffled body margin and molecular data ( Litvaitis & Newman 2001; Newman & Cannon 1997; Rawlinson & Litvaitis 2008). Within species of Pseudobiceros , color patterns have more taxonomic value than details of the reproductive anatomy ( Newman & Cannon 1997), a view that has been demonstrated by molecular data ( Litvaitis & Newman 2001; Newman & Cannon 1994; 1995; 1997). It is therefore essential to examine live specimens and record their color patterns in vivo ( Newman & Schupp 2002).

To date, 37 species of Pseudobiceros have been described ( Bolaños 2010). P. uniarborensis was originally described as opaque black in color with three extremely narrow marginal bands ( Newman & Cannon 1994). Later, it was shown that this species shows a range of color patterns around the world including black with irregular white spots ( Australia); semi-transparent brown with or without irregular white spots ( Papua New Guinea); semitransparent, and light brown (the Philippines) ( Newman & Cannon 1997). Based on the color and color pattern categorization of Newman and Cannon (1994) the specimens found in the present study belong to the second group. In terms of their color pattern, our specimens also closely resemble those shown in the multimedia CD by Newman and Cannon (2005), originating from the Red Sea.

P. uniarborensis is recorded for the first time from the Gulf of Oman, extending the geographical distribution from the Red Sea ( Newman & Cannon 2005) to the Western Indian Ocean. Considering the uncommon occurrence of this species in the Gulf of Oman and not in the Persian Gulf, it seems that P. uniarborensis is sparsely distributed along the Iranian coasts, maybe due to different physico-chemical environment of the Persian Gulf compared with the Gulf of Oman as mentioned above for M. makranica ..

Figures

FIGURE 1. Map of the Western Indo-Pacific including the Persian Gulf and Gulf of Oman. Sampling stations are indicated by numbers (stations 30 – 35 located at Qeshm Island).

FIGURE 4. Pseudobiceros uniarborensis. Live specimens.

FIGURE 10. Field photography of Iranian polyclads presented here: (A – C) marine polyclads associated with ascidians (A) Maritigrella makranica (B) Pseudobiceros uniarborensis (C) Thysanozoon brocchii (D) Tytthosoceros lizardensis along with red algae.