Dendrodoris nigra
Creators: name: Maniei, Fatemeh
name: Wägele, Heike
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Nudibranchia
Dendrodorididae
Dendrodoris
Dendrodoris nigra

description: Dendrodoris nigra (W. Stimpson, 1855)
Figs 2A–B, 3–4, 5A
Dendrodoris nigra – Yonow 2012: 53, fig. 57 (Oman) and references therein.
Diagnosis
Colouration usually black or dark grey. Body soft, without spicules; mantle margin delicate; more than 5 gill branches; oral tentacles absent. Ptyalin glands and salivary glands present; oesophagus characterised by a highly glandular epithelium. Penis with spines; vestibular gland present (Valdés et al. 1996; Brodie et al. 1997; Valdés & Gosliner 1999; Wägele et al. 1999; Yonow 2012).
Material examined
IRAN • 12 specs; Bandar Lengeh; 26°33′29″ N, 54°52′50″ E; intertidal; Mar.–Apr. 2015; Fatemeh Maniei leg.; ZMH 141488.
Description
GENERAL APPEARANCE. Body length of the 12 preserved animals: 10–24 mm. Live animals elongate with a soft body, the almost smooth mantle margin forming a wavy edge. Two colour variants observed: black mantle, with many white to yellow spots and with a pale red band around the mantle (Fig. 2A), or black mantle with white spots and a thick distinct red submarginal band around the notum margin and around foot margin, bordered by an outer yellow band (Fig. 2B). Rhinophores always black with a white apex and ca 12 lamellae on each clavus. Six pinnate gills present, arranged in a circle around the anus and curved inwards in life.
HISTOLOGY. One black specimen with a distinct red submarginal band (length of preserved animal 19 mm) was examined histologically. The slide series is deposited in the histology collection of the LIB, Museum Koenig Bonn, without a number.
INTEGUMENT. Epidermis of the mantle composed of cuboidal cells with mucus cells interspersed; mucus cells with homogeneously stained purple or with dark purple grana (acid mucopolysaccharides) (Fig. 3A). Epithelium of hyponotum with cuboidal or flat cells and fewer glandular cells. Melanin grana lying subepidermal, distributed in patches.
DIGESTIVE SYSTEM. Mouth area surrounded by a thick violet stained glandular layer containing high columnar cells. Oral tube with cuboidal to columnar cells, interspersed with reddish stained glandular cells (Fig. 3B). A paired ptyalin gland present with separate ducts leading into one central muscular duct finally opening dorsally into the oral tube, close to the transition into the pharynx; cells of ptyalin gland with pyknotic nuclei and no visible contents, thus creating a spongy appearance. Ducts inside the gland composed of glandular cells with pale bluish stained grana. Labial disc with reddish staining subepithelial glandular cells, and without cuticle (Fig. 3B). The pharynx with a triangular-shaped lumen. Epithelium consisting of cuboidal to elongate cells, covered at least in the proximal part of pharynx by a very thin cuticle. Glandular cells absent. Two muscular layers surrounding the pharyngeal epithelium; the inner one with fibres oriented transversely, which enlarge the lumen when contracted; the outer layer with fibres arranged circularly, which serve to reduce the lumen of the pharynx, and lengthen it (Fig. 3B). Salivary glands small, with small spherical cells filled with pale bluish stained grana and large nuclei (Fig. 3C). Oesophagus thicker in the cross section than the pharynx. Epithelium of the oesophagus highly folded, consisting of high columnar glandular cells staining light to dark violet (Fig. 3C). In some areas these cells with granular, in others with homogeneously stained contents. Ciliated cells interspersed. Stomach sac-like and fully embedded within digestive gland, with folded epithelium; cells elongate and ciliate (Fig. 3D). Digestive gland lobulated or folded on dorsal side, with gonad and kidney lying in these folds. Intestine arising from the embedded stomach; its folded epithelium surrounded by an inner circular and outer longitudinal muscle layer. Epithelial cells of the intestine elongate, ciliated, and non-glandular (Fig. 3E). No caecum and typhlosole observed.
REPRODUCTIVE SYSTEM. A general outline of the reproductive system is given in Fig. 5A. Gonad forming thick layer on dorsal side above the digestive gland, composed of separate areas of oocyte and spermatocyte production. Sausage-shaped ampulla filled with autosperm. Epithelium of ampulla formed by cuboidal cells (Fig. 3F). Prostatic part of vas deferens with subepithelial glandular layer, gland cells with pale bluish stained grana (Fig. 4A). Penis very long, without cuticle, but with spines. Receptaculum seminis surrounded by muscle layer; sperm heads oriented or attached to the rather flat epithelial cells (Fig. 3C). Bursa copulatrix filled with degrading sperm, prostatic material and few eggs; epithelium partly composed of apocrine secreting cells. Bursa connecting to short distal vaginal duct, the latter opening in a common vestibulum with vas deferens. Nidamental glands already large despite the small size of the animal, consisting of three areas, staining in different shades from red to bluish and dark violet. Vestibular gland large, partly lying in the body cavity, partly in the lateral body tissue (Fig. 3C); connecting to distal oviduct. Its heavily folded epithelium consisting of small, dark blue stained cells with a thick layer of microvilli in which symbiotic bacteria appear to reside (Fig. 4B).
NERVOUS SYSTEM. Cerebropleural complex at the transition of pharynx into the oesophagus. Statocyst with many otoconia (Fig. 4C).
CIRCULATORY SYSTEM. Ventricle very muscular. Blood gland close to cerebropleural complex, containing small, dark blue, stained cells (Fig. 4D).
EXCRETORY SYSTEM. Kidney lying intermingled between gonad and digestive gland; with large cuboidal cells with no stained contents (Fig. 4E). Syrinx very large, forming bulb-like structure with highly folded epithelium and long cilia (Fig. 4F).
Additional features
Body cavity surrounded by a very thick muscle layer, especially in the hind part of the body. A large retractor muscle originating close to the gills, dividing into two main muscles leading ventrally towards the anterior part, finally fusing with a strong ventral muscle layer in the anterior body. Small gill glands with pale bluish cytoplasm and large nuclei present at the base of the gills, opening into the gill pocket.
description: Published as part of Maniei, Fatemeh & Wägele, Heike, 2024, Dendrodorididae (Heterobranchia, Nudibranchia) from Persian Gulf with a description of a new species of Doriopsilla and remarks on the family, pp. 179-217 in European Journal of Taxonomy 943 (1) on pages 187-191, DOI: 10.5852/ejt.2024.943.2595, http://zenodo.org/record/12723215