Gnesioceros sargassicola ( Mertens, 1833 )

Cuadrado, Daniel, Rodríguez, Jorge, Moro, Leopoldo, Grande, Cristina & Noreña, Carolina, 2021, Polycladida (Platyhelminthes, Rhabditophora) from Cape Verde and related regions of Macaronesia, European Journal of Taxonomy 736, pp. 1-43 : 32-33

Gnesioceros sargassicola ( Mertens, 1833)

Figs 1B , 7L

Planaria sargassicola Mertens, 1833: 13–14 , pl. I, figs 4–6.

Stylochus Mertensi Diesing, 1850: 216 .

Stylochus sargassicola – Ehrenberg 1836: 67. — Claparède 1861: 143.

Planocera sargassicola – Örsted 1844: 48.

Gnesioceros sargassicola – Diesing 1862: 571.

Gnesioceros Mertensi – Diesing 1862: 572.

Stylochus Mertensi – Moseley 1877: 23.

Material examined

CANARY ISLANDS – Gran Canaria Island • 1 spec.; Pasito Blanco ; 27°44′50.46″ N, 15°37′31.85″ W ( Fig. 1B C1 ); 4 Jan. 2017; Leopoldo Moro leg.; RCCN. – Tenerife Island • 1 spec.; 28°24′35.71″ N, 16°18′25.31″ W ( Fig. 1B C 2 ); 7 Jun. 2011; Leopoldo Moro leg. RCCN .

Distribution

Bermuda Islands ( Hyman 1939); Sargasso Sea, Caribbean Sea, Atlantic Ocean ( Faubel 1983); Gulf of Mexico ( Hyman 1954); Atlantic Ocean ( Moseley 1877); Boa Vista Island, Cape Verde ( Laidlaw 1903); Santa Marta, Colombia ( Quiroga 2008); Netherlands, Puerto Rico, Florida, USA, Sargasso Sea, Atlantic Ocean ( Marcus & Marcus 1968).

New records

Pasito Blanco, Gran Canaria, and Tenerife, Canary Islands.

Remarks

Gnesioceros sargassicola was limited to the Antilles and the Caribbean Sea until the record of Laidlaw (1903) for the Cape Verde Islands. The new record of G. sargassicola for the Canary Islands shows a progressive ‘colonisation’ of the Atlantic east coast.

Molecular analysis

The main purpose of the 28S analysis was to confirm the determinations made from the morphological study and verify the relationships among similar species.

The recovered topology by both trees, Bayesian Inference (BI) as well as Maximum Likelihood (ML) strongly supports the monophyly of the suborders Acotylea and Cotylea (Fig. 8; Acotylea : BPP (Bayesian

posterior probabilities) = 1 and BS (Bootstrap values of ML analysis) = 73, Cotylea : BPP = 0.98, BS = 100).

Within Acotylea , the monophyly of Leptoplanoidea (BPP = 1, BS = 97) and Stylochoidea (BPP = 1, BS = 73) is well supported. Callioplana marginata Stimpson, 1857 considered within the superfamily Stylochoidea appears isolated with the highest support (BS = 100).

As a sister group of Leptoplanoidea , there is a clade of species: Ilyella gigas ( Schmarda 1859) , Discocelis tigrina ( Blanchard, 1847) , Adenoplana evelinae Marcus, 1950 , Amemiyaia pacifica Kato, 1944 and Phaenocelis medvedica Marcus, 1952 showing low support and not clearly grouped (Fig. 8).

The main group of Leptoplanoidea encloses the family Leptoplanidae , with the genera Leptoplana Ehrenberg, 1831 and Armatoplana Faubel, 1983 , and the family Notoplanidae Marcus & Marcus, 1966 with the genera Notoplana Laidlaw, 1903 and Notocomplana Faubel, 1983 . Pseudostylochus Yeri & Kaburaki, 1918 and Koinostylochus Faubel, 1983 appear together and belong to the family Pseudostylochidae Faubel, 1983 .

Within Stylochoidea , four main clades are recovered: family Stylochidae with the genera Stylochus , Imogine Girard, 1853 and Paraplanocera Laidlaw, 1903 (see the Discussion); family Latocestidae Laidlaw, 1903 with Leptostylochus Bock, 1925 and Latocestus ; family Hoploplanidae StummerTraunfels, 1933 with Hoploplana Laidlaw, 1902 and finally family Planoceridae with Paraplanocera Laidlaw, 1903 and Planocera . Callioplana marginata can be considered a sister group of Stylochoidea .

Within the suborder Cotylea , the families Cestoplanidae Lang, 1884 , Pericelidae Laidlaw, 1902 and Anonymidae represented by the genera Cestoplana Lang, 1884 (BPP = 1, BS 100), Pericelis (BPP = 1, BS 100) and Anonymus (BPP = 1, BS 100), respectively are presented as isolated groups. While Boninia Bock, 1923 , Chromyella Correa, 1958 and Theama Marcus, 1949 form a well-supported group (BPP = 1, BS = 100), although currently belonging to separate families and not specifically related to each other.

After Anonymidae , we find a well-supported branch (BPP = 0.9, BS = 95) that encompasses the families Prosthiostomidae Lang, 1884 , Euryleptidae and Pseudocerotidae . This branch is, in turn, divided into two main branches (both supported by maximum values: BPP = 1, BS = 100) where Prosthiostomidae is separated from Euryleptidae and Pseudocerotidae , families with a clear relation.

Figures

Fig. 1. Location of sampling points, distribution of the Macaronesian archipelagos and limitation of regions: Lauri-Macaronesia or Lusitanian Macaronesia (white); Central Macaronesia or Eumacaronesia (bordeaux) and Great Macaronesia (green). Abbreviations:A1 = San Miguel Island, Azores; C1 = Pasito Blanco, Gran Canaria, Canary Islands; C2 = Tenerife, Canary Islands; C3 = Garachico, Tenerife, Canary Islands; C4 = Amarilla Golf, Tenerife, Canary Islands; CV1 = Astillero Mindelo, S„o Vicente Island, Cape Verde; CV2 = Bahía das Gatas, S„o Vicente Island, Cape Verde; CV3 = Calheta Funda, Sal Island, Cape Verde; M1 = Ifni, South Morocco; M2 = Agadir, South Morocco.

Fig. 7. A. Anonymus ruber Cuadrado, Moro & Noreña, 2017 from Cape Verde. B. Cycloporus gabriellae Marcus, 1950 from Cape Verde. C. Prostheceraeus moseley Lang, 1884 from Cape Verde. D. Pseudoceros velutinus (Blanchard, 1847) (transmitted light) from Cape Verde. E. Monobiceros langi Faubel, 1984 from Cape Verde. F. Stylochus pilidium (Götte, 1881) from South Morocco. G. Stylochus pillidium (Götte, 1881) from Azores. H. Stylochus sp. from South Morocco. I. Stylochus neapolitanus (Delle Chiaje, 1841–1844) from Madeira. J. Planocera pellucida (Mertens, 1833) from Canary Islands. K. Discocelis tigrina (Blanchard, 1847) from Canary Islands. L. Gnesioceros sargassicola (Mertens, 1833) from Canary Islands.

Fig. 2. Marcusia alba sp. nov. (MNCN 4.01/2620 to 2683).A. Whole live animal, dorsal view.B. Anterior region with cerebral eyes cluster and pseudotentacles (white arrows). C. Histological section of the male copulatory organ stained with AZAN. D. Histological section of the female copulatory organ stained with AZAN. E. Sagittal reconstruction of the reproduction system. Abbreviations: see Material and methods.