Platytyphlops orbicularis
Creators: name: Roccatagliata, D.
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Cumacea
Lampropidae
Platytyphlops
Platytyphlops orbicularis

description: Platytyphlops orbicularis (Calman, 1905)
Figs. 7, 8C–E
Platyaspis orbicularis Calman, 1905: 43, Figs. 77–81.
Platytyphlops orbicularis — Stebbing, 1912: 144, 161 (in part); 1913: 158, 159 (in part, catalog). — Zimmer, 1980: 18 (in part). — Gerken, 2018: 139 (key), 145, 158, 181 (in part).
Platysympus orbicularis — Hansen, 1920: 52.
Paralamprops orbicularis — Reyss, 1978a: 12 [“Sta. 44, 1 specimen ”, Biscay Bay, RV Sarsia]. — Day, 1978: 148 (in part, key). — B˘acescu, 1988: 25 (in part, catalog). — Jones, 1990: 78, 80 (tables). — Gerken and Watling, 1999: 203, 204. — Watling and Gerken, 2005: 139 (table).
3.2. Material examined
THALASSA 70, Sta. W357, 43 ◦ 37 ′ N, 02 ◦ 19.2 ′ W, 770 m, 04 Oct 1970: 3 SA ♀♀, 2 A ƋƋ, 1 SA Ƌ (MACN-In. 44073). BIOGAS II, Sta. DS33, 47 ◦ 39.7 ′ N, 08 ◦ 05.5 ′ W, 2338 m, 20 Apr 1973: 1 juv. (MACN-In. 44074).
3.2.1. Description of the adult male (habitus and appendages description are based on specimens MACN-In. 44073a and MACN-In. 44073b)
Total length: 8.2 mm.
Carapace (Figs. 7A and 8C, D) dorso-ventrally flattened; approximately as long as wide, broadly rounded anteriorly. With a marginal carina; a double mid-dorsal carina runs from anterior margin of frontal lobe to anterior end of a wide median gutter; a pair of submedian carinae at each side of the wide median depression, which extends almost to posterior margin (these carinae become more evident when the specimen is inclined, see Fig. 8D). Marginal carina without teeth. Pseudorostral lobe longer than ocular lobe, with a median notch (visible in dorsal view). Ocular lobe triangular, no lenses. Frontal lobe not interrupted dorsally, i.e., ocular lobe separated from frontal lobe by frontal suture.
Free thoracic segments (Fig. 7A) 0.7 as long as carapace.
Abdomen very long, without carinae, 1.33 times as long as cephalothorax.
Pleonites 1–5 increasing in length backwards. Pleonite 6 1.52 times longer than wide.
Telson (Fig. 7D). 1.54 times as long as pleonite 6.
First antenna (Fig. 7B). Peduncle, article 1 1.33 times as long as articles 2 and 3 together. Article 2 1.69 times article 3. All three articles with many setulate setae. Main flagellum shorter than peduncle, composed of 5 articles, article 1 thicker and with a large number of aesthetascs (2 of them fully drawn, remaining ones cut basally), article 4 with an aesthetasc distally; article 5 minute, with an aesthetasc halfway along article. Accessory flagellum 0.9 as long as main flagellum, composed of 4 articles, last one minute.
Fifth pereopod (Fig. 7C) minute, without setae (except for dactylus distal seta), slightly longer than half its pereonite, approximately 0.25 as long as basis of pereopod 4. All articles distinct.
Uropod (Fig. 7D). Peduncle 1.71 times as long as telson, inner margin with approximately 30 robust setae (only the seta socket usually remains). Rami broken.
Penial papillae (Fig. 7C), without setae or elaboration, extending from the genital pores.
3.2.2. Description of the subadult female (habitus based on specimen MACN-In. 44073c and MACN-In. 44073d)
Total length: 9.6 mm.
Carapace (Fig. 7E) as adult male, except for nearly circular in dorsal view, 1.08 times wider than long. Middorsal carina single, finely denticulated (with microscopic teeth only visible under high magnification).
Fifth pereopod (Fig. 8E), even shorter than in the male, without setae (except for dactylus distal seta), less than 0.5 as long as its pereonite, approximately 0.2 as long as basis of pereopod 4. All articles distinct.
The poor condition of the specimens prevents further description.
3.2.3. Distribution
North-East Atlantic, 423–2338 m (see Fig. 1, Table 1).
description: Published as part of Roccatagliata, D., 2023, The genus Platytyphlops (Cumacea: Crustacea): A new species from Argentina, taxonomic status of Platytyphlops orbicularis (Calman, 1905), and remarks on the genus, pp. 284-292 in Zoologischer Anzeiger 302 on pages 289-290, DOI: 10.1016/j.jcz.2022.12.008, http://zenodo.org/record/10375815