Stylochus salis, Cuadrado & Rodríguez & Moro & Grande & Noreña, 2021

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 : 22-23

Stylochus salis sp. nov.

urn:lsid:zoobank.org:act:8A640FC8-D74C-4617-9766-F0FB9806BD4B

Figs 1C , 5 A–D

Etymology

The name of the new species, Stylochus salis refers to the type locality, Sal, a Cape Verdean Island.

Material examined (2 specs)

Holotype CAPE VERDE • Sal Island , Calheta Funda ; 16°39′03.34″ N, 22°56′42.94″ W ( Fig. 1C V 3 ); 12 Nov. 2018; Leopoldo Moro leg.; MNCN 4.01/2719 to 2723 (5 slides). One sagittal sectioned specimen stained with AZAN.

Additional material

CAPE VERDE • 1 spec.; Sao Vicente Island , Mindelo ( Fig. 1C V1 ); 16°53′46.54″ N, 24°59′32.93″ W; 6 May 2017; Leopoldo Moro leg.; RCCN .

Description

BODY. Shape elongated. Length 0.4 cm. Smooth dorsal surface. Background pigmentation cream white with an orange internal outline, sometimes interrupted, along the body margin and bordered by a white/ creamy outer band ( Fig. 5A ). Few cerebral and marginal eyes, scattered between the tentacles and anterior end ( Fig. 5C ). Two small nuchal tentacles with abundant basal eyes ( Fig. 5B ). Ruffled pharynx in the middle of the body and the oral pore in the end of the pharynx pouch and close to the gonopores. Male and female gonopores located close together in the posterior end of the body.

MALE REPRODUCTIVE SYSTEM. Male copulatory organ backwards oriented and provided with an inconspicuous unarmed penis papilla. Prostatic vesicle muscular with granular lining (polyglandulartype after Bulnes et al. 2005) ( Fig. 5D ). Seminal vesicle elongated, empties at the distal end of the prostatic vesicle. The short penis papilla and ejaculatory duct emerge in a small male atrium ( Fig. 5D ).

FEMALE REPRODUCTIVE SYSTEM. Shows the characteristic configuration of the genus. A tubiform canal with s-shaped ending in a small widening.

Remarks

Stylochus salis sp. nov. belongs to the genus Stylochus due to the presence of gonopores separate and arranged in the second body half. With large and much ruffled pharynx. Tentacular, cerebral, marginal, and often frontal eye-spots present. Male copulatory apparatus with seminal vesicle and papillate penis. Lang’s vesicle lacking (after Faubel 1983).

Stylochus salis sp. nov. clearly differs from other known species of Stylochus Ehrenberg, 1831 by its peculiar cream pigmentation bordered with the internal orange outline and the white/creamy outer band. The color of the eastern Atlantic known species ( S. alexandrinus , S. castaneus Palombi, 1939 , S. neapolitanus , S. plessissii Lang, 1884 , and S. suesensis Ehrenberg, 1831 ) varies between brown, light brown, reddish or beige and spotted as in S. neapolitanus . None of them present a continuous (or discontinuous) marginal line.

The most conspicuous anatomical feature is the location of the oral pore, very close to the gonopore, clearly different from the central position of the oral pore in this genus. The peculiar location of the oral and genital pores distinguishes S. salis sp. nov. from the remaining species. Such a close location of the pores could only be found in the genus Latocestus Plehn, 1896 ( Latocestidae, Stylochoidea ).

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. 5. A–D. Stylochus salis sp. nov. (MNCN 4.01/2719 to 2723). A. Whole live animal, dorsal view. B. Anterior region with eyes cluster and tentacles (black arrows). C Whole live animal ventral view. D. Histological sagittal sectionsof the reproductive system and sagittal reconstruction.–E–H. Distylochus fundae sp. nov. (MNCN 4.01/2724 to 2725). E. Whole live animal, dorsal view. F. Anterior region with cerebral eyes and tentacles (white arrows). G. Histological sagittal section of the reproductive system. H. Sagittal reconstruction of reproductive system. Abbreviations: see Material and methods.

Fig. 3. A–D. Prostheceraeus crisostomum sp. nov. (MNCN 4.01/2684 to 2698). A. Whole live animal, dorsal view. B. Anterior region with cerebral eyes cluster and tentacles (black arrows). C. Histological section of the reproductive system stained with AZAN. D. Histological section of the whole animal stained with AZAN and sagittal reconstruction. – E–I. Pseudoceros rawlinsonae var. galaxy (MNCN 4.01/2729 to 2798). E. Whole live animal, dorsal view. F. Anterior region with eyes cluster and tentacles (white arrows). G. Whole live animal, ventral view. H. Histological sagittal section of male and female copulatory organ. I. Sagittal reconstruction of the reproductive system. Abbreviations: see Material and methods.