Sepietta obscura, Naef, 1916

Wild, Elvira, Wollesen, Tim, Haszprunar, Gerhard & Heß, Martin, 2015, Comparative 3 D microanatomy and histology of the eyes and central nervous systems in coleoid cephalopod hatchlings, Organisms Diversity & Evolution (New York, N. Y.) 15 (1), pp. 37-64 : 44-46

publication ID	https://doi.org/ 10.1007/s13127-014-0184-4
persistent identifier	https://treatment.plazi.org/id/B94787AC-FFFE-D24B-FC93-19BDC2EAFAF9
treatment provided by	Felipe
scientific name	Sepietta obscura
status

Treatment

Sepietta obscura View in CoL

The hatchling of S. obscura ( Fig. 13 View Fig , supplement interactive Fig. 3 View Fig ; horizontal head diameter ca. 2.5 mm) has a slender body with some dorsoventral compression in the head and arm crown region. The eyes are centered in the horizontal midline of the head ( Fig. 13a View Fig ), point laterally (Fig. 2c) and slightly upward ( Fig. 13d View Fig ). As in R. macrosoma , the corneae are surrounded by bulging outer lids. The globular eye bulbs structure preservation, e Idiosepius notoides (Richardson) , f Loligo vulgaris (Richardson) , g Octopus vulgaris (Azan) . Labels: aco=anterior chamber organ, igl=inner granular layer, ipl=inner plexiform layer, nol= medullar neuropil of optic lobes sorrounded by pericaryal islands, ogl= outer granular layer, opl=outer plexiform layer

(horizontal diameter 1,000 μm) fill the anterior chambers almost completely in their central part (except between corneae and lenses). The anterior chamber organs are poorly developed and only discernible at the posterior end of the eye ( Fig. 13e View Fig ). The retinal curvature is regular with a slight horizontal bend defining a smaller ventral and a larger dorsal retina (with slightly longer distal photoreceptor segments). Globally, the retina is subhemispherical with a slight flattening in the contact area with the optic lobe. The vitreous body is well developed like in S. officinalis and R. macrosoma ; the lens (diameter 415 μm) has a comparatively small distal segment (15 % of diameter, Fig. 3c View Fig ) and shows cortical ruptures caused by the slice preparation.

The peduncle commissure connects both peduncle lobes, and the ventral optic commissure is situated ventrally to the latter directly above the esophagus ( Fig. 6c View Fig ).

In S. obscura , brachial and pedal lobes are spaced widely and concomitant with the fact that the frontal inner parts of the optic lobes almost touch each other; there is little space left for the long bundle of brachiopedal and brachiopalliovisceral connectives ( Fig. 13e View Fig , Fig. 2c, and Fig. 10c View Fig ). Oculomotoric and upper antorbital nerves are tracable over a short distance, emerging frontally from the pedal lobes ( Fig. 7c View Fig and Fig. 10c View Fig ). This steric situation also forces the frontal lobes apart from the buccal and brachial ones ( Figs. 8c View Fig and 9c View Fig ) and results in elongated cerebrobrachial connectives and shortened buccobrachial connectives. As in R. macrosoma , cerebrobuccal connectives could not be tracked, albeit indicated in histological sections, and the dorsal basal lobes are rather narrow (Fig. 2c).

The statocysts (max. diameter ca. 590 μm) show signs of shrinkage, but its pronounced dorsoventral flattening is native. The olfactory organs lie ventrolaterally behind the eyes, flattened oval structures (350×300×50) μm 3 connected with the olfactory lobes via the olfactory nerves ( Figs. 13a,e View Fig and 8c View Fig ).