Holophryxus alaskensis Richardson 1905

• Main Authors: Huys, Rony, Savchenko, Alexandra S., Kosobokova, Ksenia N.
• Format: Other/Unknown Material
• Language: unknown
• Published: 2023
• Subjects: Biodiversity; Taxonomy; Animalia; Arthropoda; Malacostraca; Isopoda; Dajidae; Holophryxus; Holophryxus alaskensis; Mueller; Pacific; Arctic
• Online Access: https://zenodo.org/record/8011035; https://doi.org/10.5281/zenodo.8011035

HOLOPHRYXUS ALASKENSIS RICHARDSON, 1905 A Synonyms: Holophryxus californiensis Richardson, 1908; Hypodajus georgiensis Nierstrasz & Brender à Brandis, 1931. Original description: Richardson (1905a): 221–117, figs 8–10 (♀). Additional descriptions: Richardson (1905b —as Ho. alascensis): 576–577, figs 639–641 (♀). Richardson (1908 — Ho. californiensis): 692–694, figs 4, 5 (♀ and ♂). Nierstrasz & Brender à Brandis (1931—as Hyp. georgiensis): 212, 213, figs 106–110 (♀ and ♂). Butler (1964): 973–975, figs 1–3 (adult and immature ♀♀, and ♂). Coyle & Mueller (1981): 1439–1441, figs 1, 2 (epicaridium, microniscus, cryptoniscus and juvenile female). Boyko & Williams (2021b): 112–114, fig. 1 (♀ and ♂). Hosts: Pasiphaea pacifica (P l e o c y e m a t a, Pasiphaeidae); Paraeuchaeta elongata (Esterly, 1913) (intermediate host). Distribution: North Pacific Ocean (Table 2). Differential diagnosis: Holophryxus. Body length 6 mm (♂; N = 1) (Richardson, 1908); 10.5 mm (♀; N = 1), about 2 mm (♂; N = 1) (Nierstrasz & Brender à Brandis, 1931); 4.3–5.5 mm (immature ♀♀; N = 2); 5.5– 12.0 mm (adult ♀♀; N = 18), 1.9–6.0 mm (♂♂; N = 2) (Butler, 1964); 0.2–0.3 mm (epicaridium), 1.2 mm (cryptoniscus) (Coyle & Mueller, 1981); 13.6 mm (♀; N = 1), 2.0 mm (♂; N = 1) (Boyko & Williams 2021b). Colour in life maize (♀), in alcohol and formalin yellowish white (both sexes) (Butler, 1964); after preservation uniformly light yellow (♀) (Richardson, 1905a); canary yellow in life (♀) (Richardson, 1908). FEMALE: Body oblong-ovate, about 1.8–2.3 times as long as maximum width. Cephalon only slightly demarcated from pereon in dorsal aspect by constriction bilaterally and transverse surface fold dorsally; dorsal prominence with emarginate (bilobed) anterior margin; ventral cephalic ridge partly discernible in dorsal aspect, slightly arched, about 0.35 times as long as maximum width, anterior margin slightly sinuous, without paired pit organs; posterolateral corners of cephalic ridge with rounded processes, representing coxal ...