Holt and Tattersall, 1905
Description
— Generic features. General form compact. Eyes large, globular, no ocular papilla. Antennular peduncle thick and strong with the distal margin of the proximal segment straight and without any outgrowth. Antennal scale with outer margin entire of serrated, terminating in a strong spine beyond which the apex of the scale extends. Thoracic limbs with the endopods moderately long and with well-developed claw. Inner margin of endopod of uropod without spines. Telson in the form of a long narrow triangle. Apex of telson armed with a pair of plumose setae. Marsupium consisting of three or four pairs of brood lamaellae.
— Species. Carapace long and oblong in dorsal view, leaving only half of the last thoracio somite exposed; anterior end broadly rounded; posterior margin slightly emarginate; cephalothorax only slightly wider than abdomen.
Antennular peduncle robust with the distal segment as long as the sum of the other two segments; hirsute lobe in the male small in the type specimen (which is immature), but normally developed in older specimens.
Antennal peduncle very short; scale long and narrow, about four times as long as broad; half as long again as the antennular peduncle, outer margin without setae, but having a few, irregularly placed, coarse denticulations in addition to the terminal tooth beyond which the obliquely truncate apex extends. In young specimens of up to 5 mm. in length the outer margin shows no serrations so that, in this respect, they closely resemble young Parerythrops, from which they may readily be distinguished by the large size and pale golden colour of the eye.
Antennal scale with outer margin entire or serrated, terminating in a strong spine beyond which the apex of the scale extends.
Eyes large, globular, considerably broader than long, reaching to the distal margin of the first segment of the antennular peduncle; set somewhat widely apart and, in dorsal view, extending beyond the lateral margins of the carapace; cornea occupying over two-thirds of the whole organ, not flattened dorso-ventrally; pigment pale golden brown.
First thoracic limb robust, with well developed nail, dactylus armed with four or five strong barbed spines on the inner margin. Second thoracic limb, carpus straight, equal in length to the sum of the propodus and dactylus, the latter well developed, tapering distally and bearing a long, slender nail. Third to the eighth thoracic limbs very similar to those of Parerythrops but somewhat shorter. As in so many genera in this tribe, the thoracic legs become progressively longer on the posterior somites. Pleopods of the female simple, unjointed, setose plates which become progressively longer on the posterior abdominal somites; first pair of pleopods of the male developed as in Erythrops with the exopod well developed and many segmented and the endopod reduced to a single segment.
Telson long and narrowly triangular, about twice as long as broad at the base; lateral margins unarmed and nearly straight; narrow posterior margin armed with two pairs of slender spines and two median plumose setae; the inner pair of spines very long, almost equal to one-third of the length of the telson and more than twice as long as the outer pair.
Uropods long and slender and slightly bowed outward; exopod twice as long as the telson and half as long again as the endopod; no spines have been recorded on the inner margin of the endopod.
Colour
Pale golden brown, with patches of deep brown in the region of the stomach and on the posterior part of the thorax.
Size
Adult up to 13-15 mm long.
Depth range
Bathypelagic: 350-1800 m. It has a wide vertical range and can be regarded as mesoplanktonic in deep waters.
Remarks
This species can readily be distinguished from Parerythrops obesa by the serrations on the outer margin of the antennal scale, (except in very immature animals); the pale golden colour and the larger size of the eyes; the absence of spines on the inner margin of the endopod of the uropod and the form of the first pleopod of the male.
Distribution in the North Sea
Deep waters of the northern North Sea and the Norwegian Deep.
World distribution
Semi-cosmopolitan. Oceanic, in the Atlantic <26-65°N. This species is widely distributed in the temperate waters of both North and South Atlantic.
[After Tattersall and Tattersall, 1951]