A revision of the genus Orchestia Leach, 1814 with the reinstatement of O. inaequalipes (K. H. Barnard, 1951), the designation of a neotype for Orchestia gammarellus (Pallas 1776) and the description of three new species (Crustacea: Amphipoda: Talitridae Talitrinae)
Author
Myers, Alan A.
School of Biological, Earth and Environmental Sciences, University College Cork, Cork Enterprise Centre, Distillery Fields, North Mall, Cork, Ireland. bavayia @ gmail. com; https: // orcid. org / 0000 - 0003 - 3256 - 2123
Author
Lowry, James K.
Australian Museum Research Institute, 1 William Street, Sydney, NSW 2010, Australia.
text
Zootaxa
2020
2020-07-02
4808
2
201
250
journal article
10.11646/zootaxa.4808.2.1
1175-5326
3933375
34BA963C-33B1-42BF-8340-D332B5C0628F
Orchestia forchuensis
sp. nov.
(
Figs 12–14
)
Orchestia gammarella
.―
Bousfield, 1958: 885
, figs 1e, 10a.―
Bousfield, 1973: 159
, pl. 45.1.
Orchestia gammarellus
.―
Ingólfsson, 1996: 39
, fig. 10.―
Henzler & Ingólfsson, 2007: 1
.
Not
Orchestia gammarellus
(
Pallas, 1776
)
: 191, pl. 14, fig. 25.
Types.
Holotype
, male, 12.0 mm (
CNMC 1984-462
),
Cape
Fourchou
,
Yarmouth County
,
Nova Scotia
, 5
July
,1956,
E.L. Bousfield.
Paratypes
.
4 males
,
8 females
(
CNMC 1984-462
), same data as holotype
.
Other material studied.
3 females
,
25 juveniles
(
CNMC 1984-472
),
3 miles
west of
Le Cou Harbour
,
southwestern Newfoundland
(
47
o
38’N
58
o
41’W
),
8 June 1966
, D.E. McAllister;
2 males
,
5 females
(
CNMC 1984-465
)
Gilbert Point
,
Digby County
,
Nova Scotia, E.L
.
Bousfield
,
9 July 1958
;
3 males
,
5 females
,
2 juveniles
, (
CNMC 1984-460
), above
Murphy’s river
,
Salmonier Estuary
,
Newfoundland
, 15
August
, 1954,
E.L. Bousfield
;
7 males
,
11 females
,
Nauthólsvík
, between
Kópavogur
(pubby seal bay) and
Reykjavík
,
Iceland
(64.117714
oN
21.900876
oW
),
September 2019
,
Davíð Gíslason
;
9 males
,
10 females
, salt-marsh, under stones in the saltmarsh grass
Puccinella maritima
beds
Galgahavn
,
Iceland
(64.0549
oN
21.5728
oW
),
23 September 2019
,
Jorundur Svavarsson
.
Type locality.
Cape
Fourchu,
Nova Scotia
.
Etymology.
Named after the
type
locality.
Description of adult male
(
15 mm
).
Head.
Eyes
of moderate size.
Antenna 1
short, just reaching beyond peduncular article 4 of antenna 2; accessory flagellum absent; primary flagellum with 5 articles.
Antenna 2
peduncular article 5, 1.3 × length of peduncular article 4; flagellum longer than combined length of peduncular articles 4 and 5, with 19-20 articles, final article cone shaped, with terminal cluster of imbricated setae.
Labrum
without epistome. Mandible left lacinia mobilis with 4 cusps.
Maxilliped
palp article 2 with distomedial lobe.
Pereon.
Gnathopod 1
subchelate, coxa smaller than that of coxa 2; posterior margin of carpus and propodus each with lobe covered in palmate setae; propodus length to carpus length 1:1.6; propodus strongly triangular; dactylus shorter than palm.
Gnathopod 2
subchelate; basis 2.3 × as long as broad; merus posterior margin with 3-5 short setae; propodus weakly triangular, distal width 1.7 × proximal width.
Pereopods 3–7
bicuspidactylate, cusps sometimes becoming lost in large males.
Pereopods 3–4
dactylus unguis relatively slender, acute, becoming short and blunt on pereopod
7 in
large males
Peropod 4
dactylus thickened proximally with a notch midway along posterior margin.
Pereopod 5
basis subovoid.
Pereopod 7
basis posterior margin distinctly serrate; merus elongate, weakly triangular, becoming 2 × as wide distally as proximally in large males; carpus elongate pyriform, 1.5 – 2 × as long as broad
; carpus subequal to merus in small males, becoming 1.5 × longer in large males; propodus 1.2 × length of carpus.
Pleon.
Epimeron 3
posterior margin weakly crenulate.
Uropod 1
peduncle longer than rami, without distolateral robust seta; rami subequal.
Uropod 2
peduncle subequal in length with rami, rami subequal; exopod with 2 marginal robust setae; endopod with 3 marginal robust setae and 2 robust setae on inner face.
Uropod 3
peduncle only a little longer than broad; ramus 2.3 × as long as broad 0.6 × length of peduncle, outer margin with 6 robust setae.
Telson
with about 9 apical robust setae on each side.
Female
(sexually dimorphic characters).
Gnathopod 2
mitten-shaped; basis 2 × as long as broad, broadest proximally, anterodistal margin substraight; carpus 1.4 × length of propodus.
Pereopod 7
stout, basis posterior margin weakly serrate, merus and carpus unexpanded.
FIGURE 12.
Orchestia forchuensis
sp. nov.
, Cape Forchu, Nova Scotia, Canada.
Habitat.
Limestone, gravel and pebble beaches; marshes among the saltmarsh grass
Puccinella maritima
.
Remarks.
Orchestia forchuensis
sp. nov.
is close to
O. gammarellus
(
Pallas, 1776
)
but can be distinguished by the shape of the adult male pereopod 7 that has the merus almost parallel-sided, only about twice as broad distally as proximally in
O. forchuensis
sp. nov.
(strongly triangular, almost three times as broad distally as proximally in
O. gammarellus
) and the carpus much longer than broad (almost as broad as long in
O. gammarellus
). The basis of pereopod 5 has a weakly developed posterodistal lobe in
O. fouchouensis
sp. nov.
(well-developed in
O. gammarellus
) and the basis of the female pereopod 7 of
Orchestia forchuensis
sp. nov.
is subovoid (approaches subquadranglar
in
O. gammarellus
)
. That the North American populations of ‘
Orchestia
gammarellus’
were probably a previously unrecognised species, was first pointed out by
Perez-Schultheiss (2014
, p. 30).
Distribution.
Canada
Newfoundland: Campell’s Creek Cove, Port-au-Port peninsula; Little Bay, near Springfield; Exploits estuary; Philip’s Head; Placentia; Salmonier estuary; Trepassey, head of Mutton Bay; Fox Cove (
Bousfield 1955
); above Murphy’s river, Salmonier Estuary (present study); Gooseberry Cove (
47°03.3’N
54°05.7’W
), Kingwell Arm (
47°33.5’N
54°06.O’W),Dirty Rocks (
47°23.7’N
54°16.1’W
),Margery Cove (
47°24.5’N
54°09.0’W
) (
Fenwick & Steele 1983
), Cou Harbour, south-western Newfoundland (
47
o
38’N
58
o
41’W
) (present study).
Nova Scotia
. Machias Seal Rock; St. Andrews; Argyle (
Bousfield 1955
). Gilbert Point, Digby County,
Nova Scotia
(present study).
FIGURE 13.
Orchestia forchuensis
sp. nov.
, Cape Fouchu, Nova Scotia, Canada.
FIGURE 14.
Orchestia forchuensis
sp. nov.
, Cape Forchu, Nova Scotia, Canada (C) and Nauthólsvík, Iceland (I).
New Brunswick
. Bay of Fundy (
Bousfield 1960
); Tidal Cove; Machais Seal Islands (
Bousfield 1958
).
USA
(New
England
); coast of Maine to Casco Bay (
Bousfield 1973
).
Iceland
. Extreme southwest, from the Vestmannaeyjar Islands to Reykjavíc and the northwest peninsula area associated with warm springs; Hvassahraun (
64°01’11’’N
22°09’19’’W
) Reykjanestjörn (
63°47’52’’N
22°43’912’’W), Hveravik, Steingrimsfjördur (
65°41’47’’N
21°33’55’’W
); Bjarnarstadir, Isafjördur (
65°49’16’’N
22°2’919’’W) and Reykjanes, Reykjafjördur (
65°55’25’’N
22°25’53’’W
); Kaldrananes (
65°46’N
21°24’W
) and Skarð (
65°29’N
20°59’W
) (
Ingólfsson 1973
,
1977
,
Morritt & Ingólfsson 2000
,
Ingólfsson
et al
. 2007
,
Henzler & Ingólfsson 2007
).