Pontocrates moorei, Myers & Ashelby, 2022

Myers, Alan A. & Ashelby, Christopher W., 2022, A revision of the genus Pontocrates Boeck, 1871 (Amphipoda, Oedicerotidae) with the description of P. moorei sp. nov. and the re-establishment of P. norvegicus (Boeck, 1860), Zootaxa 5115 (4), pp. 582-598 : 586-589

Pontocrates moorei sp. nov.

( Fig. 3 , 4 )

Pontocrates arcticus Moore & Beare, 1993 . 610, figs 1, 2.—De Grave & Myers, 1997, 383.

Not Pontocrates arcticus Sars, 1895 , 693.

Type material. Holotype female; Ryde Sands; 50°44’24.14”N 001°09’04.09”W; intertidal, lower shore; Sand and Muddy Sand; leg. Natural England, 28/08/2015. ( MNINH 2021.16.1)

Paratypes 1 female; Same data as holotype ( MNINH 2021.16.2)

Other material. 1 female; Cape Clear , SW Ireland; 51°27’15.80”N 009°27’26.40”W; 28 m depth; Sand; leg. Treanbeg Marine Consulting, 01/11/2016 . 2 females; Fal Estuary ; 50°05’42.00”N 005°05’44.40”W; 13.1 m depth; Gravel; leg. Natural England, 02/05/2013 . 1 female; North Sea , UKCS 43 /13; 54°31’36.35”N 001°28’58.81”E; 34 m depth; Sandy Gravel; leg. Gardline, 31/05/2018 . 1 male; North Sea , UKCS 44 /12; 54°34’08.40”N 002°17’24.00”E; 23 m depth; Muddy Sand; leg. Gardline, 16/03/2018 . 1 female, North Sea , UKCS 44 /12; 54°34’08.40”N 002°17’24.00”E; 23 m depth; Sand; leg. Gardline, 16/03/2018 . 1 female North Sea , UKCS 43 /13; 54°33’58.67”N 002°15’45.69”E; 22 m depth; Slightly Gravelly Sand; leg. Gardline, 31/05/2018 ; 60+ females; Creeklands , Orkney; 58°55’06.43”N 003°19’15.09”W; intertidal—lower shore; Sand; leg. OICHA, 26/04/2017 . 10 females; Dunluce Castle ; 55°13’06.59”N 006°34’53.40”W; 25 m depth; Sand; leg. DAERA, 19/06/2014 . 1 male, 4 females; Dunluce Castle ; 55°13’06.59”N 006°34’53.40”W; 25 m depth; Sand; leg. DAERA, 19/06/2014 . 1 male, 5 females; Dunluce Castle ; 55°13’06.59”N 006°34’53.40”W; 25 m depth; Sand; leg. DAERA, 19/06/2014 . 1 male; Moray Firth ; 58°13’36.84”N 002°54’14.33”W; 40 m depth; Gravelly Sand; leg. APEM, 17/06/2021 . 1 female; South Falls, North Sea ; 51°34’20.50”N 001°58’21.29”E; 49 m depth; Muddy Sand with Clay; leg. CEFAS, 02/11/2014 .

Type locality. Ryde Sands

Etymology. Named for P.G. Moore, who recorded this species (as P. arcticus ) for the first time in the British Isles.

Description (female holotype 4.0 mm)

Head. Head rostrum elongate, strongly deflected, slender in frontal view, eyes confluent dorsally. Antenna 1 short; flagellum longer than peduncle, with 6 articles, Antenna 2 longer than 1; article 4 and 5 subequal in length; flagellum scarcely longer than peduncle with 6 articles.

Pereon. Gnathopod 1 coxa distal margin substraight; basis moderately stout, about 4 x as long as broad, anterior margin concave; merus with distal extension; propodus subovoid, less than twice as long as broad, palm smooth, oblique, smooth, merging imperceptibly with posterior margin and without club-shaped robust setae. Gnathopod 2 coxa subrectangular, anterior margin substraight; basis elongate, slender; carpus small but with elongate spur that extends beyond tip of propodus; propodus very elongate, slender, chelate. Pereopod 3 coxa subovoid; basis anterior margin proximally concave, distally substraight; merus anterodistal margin strongly convex; carpus and propodus short; propodus a little longer than carpus, subrectangular, distally truncate; carpus and propodus posterior margins with many stout, robust setae; merus and propodus anterodistal margins clothed in very long slender setae; dactylus small. Pereopod 5 basis anterior margin convex; merus anterodistal margin strongly convex and with exceedingly long setae; carpus short, posterior margin irregular, with long setae; propodus longer than carpus, slender, anterior margin with long setae; dactylus elongate, slender, more than one third length of propodus. Pereopod 6 basis anterior margin weakly convex; propodus short, scarcely one third length of carpus. Pereopod 7 very long, more than half body length, basis subquadriform, the posterior margin straight to weakly concave and with a distinct posterodistal lobe; merus, carpus, propodus and dactylus very long and slender.

Pleon. Epimera 1–3 rounded. Uropods 1–2 slender; peduncles extending about the same length; peduncles subequal with subequal rami. Uropod 3 slender; subequal rami longer than peduncle. Telson distally rounded, not incised.

Male (sexually dimorphic characters). Antenna 2 longer than body length, flagellum with about 35 articles.

Colour According to Moore & Beare (1993), the body is colourless with no pigment spots of any description, the eye is red with white reticulation (eyes abut, though with a narrower facetless white strip in the mid-line than in P. arenarius ) and the sternal plates are unpigmented. The egg colour is yellow.

Habitat and distribution. Currently only known with certainty from Britain and Ireland. Present on all British coasts, extending from the Orkney Isles in the north to the English Channel in the south. Also present in Ireland and Northern Ireland. Found from the mid-shore level to depths of 35 m in offshore areas.

Substrates have included, muddy, fine, coarse and gravelly sand and gravel.

Remarks. Pontocrates moorei sp. nov. is similar to P. arcticus Sars , but it differs from that species in a number of ways. The rostrum is elongate and parallel sided in frontal view (short and triangular in P. arcticus ). The gnathopod 1 coxa distal margin is substraight (convex in P. arcticus ), the basis anterior margin is concave (substraight in P. arcticus ) the merus has a distal slender extension (blunt and lacking extension in P. arcticus ) and the propodus palm is weakly oblique, smooth and lacking club-shaped setae (strongly oblique, fimbriate, with club-shaped setae in P. arcticus ). The pereopod 3 coxa is subovoid, (subrectangular in P. arcticus ), the basis anterior margin is convex distally (substraight in P. arcticus ) and the carpus and propodus are short and broad (elongate and slender in P. arcticus ). The pereopod 6 propodus is short, about one third length of carpus (subequal with carpus in P. arcticus ) and the pereopod 7 basis is subquadriform (pyriform in P. arcticus ).

Life history traits of P. moorei (as P. arcticus ) were described by Beare & Moore (1998).

Figures

FIGURE 3. Pontocrates moorei sp. nov. Ryde Sands.

FIGURE 4. Pontocrates moorei sp. nov. Ryde Sands.