Discovery of a new species and host record of Holophryxus Richardson, 1905 (Isopoda: Dajidae) from the central Arctic: a model of enhanced descriptive standards for epicaridean isopods Author Huys, Rony Author Savchenko, Alexandra S. Author Kosobokova, Ksenia N. text Zoological Journal of the Linnean Society 2023 2023-03-27 198 2 592 649 http://dx.doi.org/10.1093/zoolinnean/zlac105 journal article 54530 10.1093/zoolinnean/zlac105 4a724d97-0468-403d-b52d-4f44d0e3d3e9 0024-4082 8011009 A9963447-9E12-4AAC-9CC3-5D165A757EF7

Table 2. Distribution and host records of all nominal species of Holophryxus Richardson, 1905a [eight valid and two species inquirendae (Ho. septapodus, Ho. truncatus)]. ‘Unknown’ means that the parasite was found free in the plankton haul, presumably having become secondarily detached from its host, or, alternatively, was found among preserved museum material; ‘w.’ refers to the length of the trawl warp used (wire out) and does not necessarily reflect the depth at which the specimens were collected. Type localities marked by *

Species	Host(s)	Locality	Depth	Reference
1 As Ho. californiensis Richardson, 1908 —synonymized by Butler (1964). 2 As Hypodajus georgiensis Nierstrasz & Brender à Brandis, 1931 [synonymized by Butler (1964)]. 3 Richardson (1905a) reported three females from two different localities but did not specify which of these specimens the illustrations were based on. Since no holotype was fixed all specimens of the type series are automatically syntypes (cf. Butler, 1964: 971) and the type locality encompasses all of their respective places of origin (ICZN Art. 73.2.3). 4 Richardson (1908) listed the host as Gennadas borealis Rathbun, 1902. Gurjanova (1936: 260) included this record in her checklist of Bering Sea isopods. Nagler et al. (2020: table 1) erroneously cited Gurjanova as the source for records of Ho. giardi associated with Bentheogennema borealis (Rathbun, 1902) at 2000 m depth in the Bering Sea, the Yellow Sea (note that Gurjanova provided a checklist for the Sea of Japan, not the Yellow Sea) and the Sea of Okhotsk; the species has as yet not been recorded from the latter two seas. 5 Female specimen originally identified as ‘ Holophryxus sp. (Ho. Richardi Koehler?)’; identification subsequently corroborated by Stephensen (1915). 6 The host was listed as Sergestes arcticus Krøyer, 1855. 7 All specimens were found free but the likely host, Eusergestes arcticus, was reported from the same station or trawl. 8 Nagler et al. (2020: table 1) lists a record of Ho. richardi associated with Sergestes arcticus from 2500 m depth at 31°40’N, 36°55’W and mistakenly attributed it to Gurjanova (1932); there is no doubt that this is a duplication of Koehler’s (1911) record which is also listed by Nagler et al. (2020) but without mention of the host. 9 Type host originally identified by Stephensen (1912) as Acanthephyra purpurea A. Milne Edwards, 1881 but later corrected to Acanthephyra multispina Coutière, 1905 by Stephensen (1913); the latter is a junior subjective synonym of A. pelagica (see Wasmer, 1986). 10 Although the host of I. concavus was unknown to Schultz (1977), the discovery of marks from the mandibles and pereopods [similar to those reported on the type host of Ho. acanthephyrae by Stephensen (1912)] on one of the specimens from the type locality led Wasmer (1988) to suggest that the host is likely to be A. pelagica. 11 Isopod name cited as the junior subjective synonym I. concavus Schultz, 1977 (cf. Wasmer, 1988). 12 Listed as ‘branchial parasite’ by Chace (1947: 12). 13 Boyko & Williams (2021b: 116) stated that the sampling coordinates of the specimens collected by Huang et al. (2018) were wrong. Huang et al. (2018) in fact provided the correct coordinates but listed the incorrect ones when describing the position of the Yilan sakura shrimp fishing ground on Guishan Island. 14 The host was listed as Sergestes prehensilis Spence Bate, 1881. 15 In addition to the type locality (Stn 10-835), Schultz (1977) recorded the species from another 17 stations (sampled during seven cruises) in the South Pacific and Southern Oceans (10-779, 10-782, 10-811, 11-900, 11-917, 11-918, 13-1120, 13-1129, 14-1186, 14-1204, 15-1302, 15-1303, 17-59-22, 17-69- 28, 17-77-32, 19-1456, 19-1463). For coordinates and depth data see Schultz (1977: 123–127). 16 Based on a juvenile female specimen; possibly conspecific with either of the known Atlantic species (Ho. acanthephyrae, Ho. richardi) or representing an undescribed species (cf. Boyko & Williams 2021b).
Ho. alaskensis	Pasiphaea pacifica Rathbun,	South-eastern Alaska: Bushby	274–512 m	Richardson
Richardson, 1905a	1902	Point		(1908)1
	Pasiphaea pacifica Rathbun,	Canada: British Columbia,	77–198 m	Butler (1964)
	1902	from Granby Bay to Strait of
		Georgia, west coast of Van-
		couver Island
	Pasiphaea pacifica Rathbun,	Alaska: Prince William Sound,	100 m	Coyle &
	1902 [intermediate host:	Knight Island Passage,		Mueller
	Paraeuchaeta elongata	60°15’N, 148°00’W		(1981)
(Esterly, 1913)]
	Pasiphaea pacifica Rathbun,	Between California and Baja	1200 m	Boyko &
	1902	California: south-east of San		Williams
		Clemente Island, 32°30’N,		(2021b)
118°10’W
	Unidentified pasiphaeid	Canada: British Columbia,	366 m	Nierstrasz
	shrimp	Strait of Georgia		& Brender
				à Brandis
				(1931)2
	Unknown	South-eastern Alaska*: Behm	269–640 m	Richardson
		Canal and Lynn Canal, c.		(1905a)3
		55°51’05”N, 131°49’43”W
	Unknown	California: Santa Barbara	512 m	Richardson
		Channel		(1908)1
	Unknown	Southern California:	Unknown	Richardson
		unspecified locality		(1905b)
Ho. giardi	Boreogennema borealis	Commander Islands: Ostrov	4941 m	Richardson
Richardson, 1908	(Rathbun, 1902)	Toporkov west of Bering Is-		(1908)4
		land, 54°48’N, 164°54’E*
Ho. richardi Koehler,	Eusergestes arcticus (Krøyer,	Davis Strait: 64°22’N, 56°00’W	400–800 m w.	Stephensen
1911	1855)			(1912)5,6
	Eusergestes arcticus (Krøyer,	Norway: vicinity of Herdla,	200–380 m	Rustad (1935) 6
	1855)	Mangerfjord, Herløfjord, west
of Torskøy
	Unknown7	Norway: Herdlefjorden,	200–390 m	Greve &
		north-west of Bergen		Johannessen
				(1981)
	Unknown	North Atlantic Ocean: south of	0–2500 m	Koehler
		Azores, 33°41’N, 36°55’W*		(1911)8
	Unknown7	Davis Strait: 66°21’N, 57°04’W	800 m w.	Stephensen
				(1912)
	Unknown	Celtic Sea: 48°09’N, 8°30’W	300 m w.	Stephensen
				(1915)
	Unknown	West of Iceland: 65°20’N,	820 m w.	Hansen (1916)
27°12.5’W
	Unknown	South of Iceland: 61°30’N,	1800 m w.	Hansen (1916)
17°08’W
	Unknown7	Various localities from east of	630–1800 m	Jones &
		Galicia to Celtic Sea: 42°59’N,		Smaldon
		10°29’W–47°52’N, 09°12’W		(1986)
Ho. acanthephyrae	Acanthephyra	North-east of Brazil: Rocas Atoll,	630 m	Alves-Júnior et
Stephensen, 1912	acanthitelsonis Spence	4°19’S, 35°29’W		al. (2019)
Bate, 1888
	Acanthephyra pelagica	Labrador Sea: 60°07’N, 48°26’W*	2000 m w.	Stephensen
	(Risso, 1816)			(1912)9
	Acanthephyra pelagica	South Pacific Ocean: 47°14’S,	329 m	Schultz
	(Risso, 1816)10	132°28’W—47°08’S, 132°43’W		(1977)11
	Acanthephyra pelagica	Celtic Sea: 47°21’N,	1500 m	Jones &
	(Risso, 1816)	08°19’W–47°23’N, 08°04’W		Smaldon
				(1986)
	Acanthephyra pelagica	South Pacific Ocean: 40°01’S,	880 m	Wasmer (1988)
	(Risso, 1816)	149°57’W
	Acanthephyra purpurea A.	Greenland: Cape Farewell	2000 m	Gurjanova
	Milne Edwards, 1881			(1932)
	Acanthephyra purpurea A.	Bahamas: 23°49’N, 76°58’W	2134 m w.	Boyko &
	Milne Edwards, 1881			Williams
				(2021b)12
	Unknown	Biscay Abyssal Plain: 46°15’N,	1130–1800 m	Jones &
		10°21’W–46°30’S, 10°28’W		Smaldon
				(1986)
	Unknown	South Pacific Ocean: 57°11’S,	2297 m	Schultz
		115°03’W–57°57’S, 115°03’W		(1977)11
	Unknown	South Pacific Ocean: 58°54’S,	1336 m	Schultz
		99°18’W–58°57’S, 99°30’W		(1977)11
	Unknown	Southern Ocean: 60°14’S,	1080 m	Schultz
		94°49’W–60°18’S, 95°05’W		(1977)11
	Unknown	Southern Ocean: 60°17’S,	2379 m	Schultz
		110°15’W–60°26’S, 110°38’W		(1977)11
	Unknown	Southern Ocean: 61°57’S,	1144 m	Schultz
		102°31’W–61°44’S, 102°42’W		(1977)11
	Unknown	Southern Ocean: 68°15’S,	1098 m	Schultz
		114°42’W–68°32’S, 114°16’W		(1977)11
Ho. fusiformis	Lucensosergia lucens	North-eastern Taiwan: Yilan	80–120 m	Huang et al.
Shiino, 1937	(Hansen, 1922)	county, Guishan Island off		(2018)13
		Toucheng, 24°48’N, 121°56’E
	Lucensosergia lucens	Japan: Kyushu, west of Naka-	380–386 m	Huang et al.
	(Hansen, 1922)	Kasayama Bank off Nagasaki,		(2018)
		32°12.504’N, 128°56.631’E
	Prehensilosergia prehensilis	Japan: Sizuoka Prefecture,	Unknown	Shiino (1937) 14
	(Spence Bate, 1881)	Sizuoka (former town of
Kanbara)*
	Sergia laminata	Japan: Suruga Bay, 34°51’51”N,	1600 m	Shimomura et
	(Burkenroad, 1940)	138°38’03”E		al. (2020)
Ho. truncatus	Unknown	Southern Ocean: 62°04’S,	915 m	Schultz (1977)
(Schultz, 1977)		75°18’W–61°52’S, 75°14’W*
	Unknown	South Pacific and Southern	–	Schultz
		Oceans		(1977)15
Ho. polyandrus	Unknown	South Pacific Ocean: 35°16’S,	275 m	Schultz (1978)
(Schultz, 1978)		124°57’W*
Ho.	Unknown	Chile: off Viña del Mar, 33°08’S,	175–185 m	Schultz (1978)
quadratahumerale		72°43’W*
(Schultz, 1978)
Ho. septapodus	Unknown	South Pacific Ocean: 42°13’S,	850–1350 m	Schultz (1978)
(Schultz, 1978)		134°28’W*
Ho. citriformis sp.	Hymenodora glacialis	Arctic Ocean: 89°0.62’N,	0–4300 m w.	This paper
nov.	(Buchholz, 1874)	61°26.15’E*
Ho. sp.16	Parapasiphae sulcatifrons	Bear Seamount: 39°57.63’–	1625 m	Boyko &
	Smith, 1884	39°55.32’N, 67°33’–67°19.78’W		Williams
				(2021b)