Distylochus fundae sp. nov.

urn:lsid:zoobank.org:act: 27AE0619-D25F-48A0-8345-31D38765F732

Figs 1C, 5 E–H

Etymology

The name of the new species, Distylochus fundae sp. nov. refers to the type locality Calheta Funda in the Island of Sal.

Material examined

Holotype

CAPE VERDE • Sal Island, Calheta Funda; 16°39′03.34″ N, 22°56′42.94″ W (Fig. 1C V 3); 14 Nov. 2018; Leopoldo Moro leg.; MNCN 4.01/2724 to 2725 (5 slides). One sagittally sectioned specimen stained with AZAN.

Description

BODY. Shape elongated. Length 0.4 cm. Smooth dorsal surface. Background pigmentation orange-garnet (Fig. 5E). Cerebral and tentacular eyes, scattered between the small tentacles (Fig. 5F). Ruffled pharynx, well developed, extending along ⅔ of the body. Male and female genital pores located in the posterior half of the body, together, but clearly separated.

MALE REPRODUCTIVE SYSTEM. Male copulatory system backwards oriented, with a small penis papilla. Prostatic vesicle surrounded by muscular layers and lined with fingered granular lining, most probably polyglandular (Fig. 5 G–H). Seminal vesicle divided into two sections. A muscular and elongated proximal section, and a more rounded distal section provided with a thin wall. Both regions separated by muscle narrowing (Fig. 5H). The distal section leads to the seminal duct that opens into the prostatic duct and forms a short ejaculatory duct. The two vasa deferentia dilated to form spermatic vesicles, open into the proximal section. Male atrium small, englobing a short penis papilla (Fig. 4H).

FEMALE REPRODUCTIVE SYSTEM. Apparatus simple and backwards oriented. Comprises an elongated tube without clear differentiation between external and internal vagina and ends in a small widening, without Lang’s vesicle.

Remarks

The new species belongs to the genus Distylochus due to the presence of few scattered marginal, tentacular and cerebral eyes. Gonopores together and are located near the posterior end. Male apparatus with a short papilla and unarmed. Seminal vesicle configured in two regions, following the “doublevesicle-system” after Faubel (1983) and female apparatus simple, without Lang’s vesicle.

There are currently only three known species for the genus Distylochus: D. pusillus (Bock, 1913) recorded for Hong Kong, D. martae (Marcus, 1947) in Brazil and D. isifer (Du Bois-Reymond, 1955) also from Brazil. These species were described on fixed specimens, therefore the colors are unknown, but apparently and after the original descriptions, they have pale pigmentation that contrast sharply with the orange-vermilion colors of the new species.

The most conspicuous difference of the new species is the disposition of female and male gonopore. In Distylochus fundae sp. nov. the gonopores are clearly separated, while in the Brazilian species are common and in the Chinese species are very close together.

New records

Following the known species that are captured in the study area. All of them have been studied through photographs and histological sections, currently in RCCN.