Podocerus ferreus, Hughes, 2013

Hughes, L. E., 2013, Podoceridae of Tropical Australia (Peracarida: Amphipoda), Records of the Australian Museum 65 (1), pp. 1-37 : 9-13

Podocerus ferreus sp. nov.

Figs 8–9

Type locality. Iron Ore Wharf , Darwin Harbour, Northern Territory, Australia (12.4725'S 130.8428'E).

Etymology. Ferreus is Latin for “of iron”, in reference to the type locality.

Type material. Holotype male, 4.4 mm, dissected, 2 slides, MAGNT Cr017407, Iron Ore Wharf, Darwin Harbour (12.4725'S 130.8428'E), wharf pylon scrapings, 16 August 1998, coll: MAGNT / CSIRO Survey Team; paratype female, 4.7 mm, dissected, 1 slide, MAGNT Cr017408, Iron Ore Wharf, Darwin Harbour (12.4725'S 130.8428'E), wharf pylon scrapings, 16 August 1998, coll: MAGNT / CSIRO Survey Team; paratype male, 4.8 mm, SEM pin mount, AM P.85670, Iron Ore Wharf, Darwin Harbour (12.4725'S 130.8428'E), wharf pylon scrapings, 16 August 1998, coll: MAGNT / CSIRO Survey Team; paratypes 10+ specimens, MAGNT Cr015652, Iron Ore Wharf, Darwin Harbour (12.4725'S 130.8428'E), wharf pylon scraping, 16 August 1998, coll: MAGNT / CSIRO Survey Team; paratypes 2 specimens, MAGNT Cr015540, Iron Ore Wharf, Darwin Harbour (12.4725'S 130.8428'E), wharf pylon scrapings, 28 March 1999, coll: MAGNT / CSIRO Survey Team; paratypes 5 specimens, MAGNT Cr015584, Iron Ore Wharf, Darwin Harbour (12.4725'S 130.8428'E), wharf pylon scraping, 28 March 1999, coll: MAGNT / CSIRO Survey Team; paratypes 6 specimens, MAGNT Cr015589, Iron Ore Wharf, Darwin Harbour (12.4725'S 130.8428'E), wharf pylon scrapings, 28 March 1999, coll: MAGNT / CSIRO Survey Team; paratypes 3 specimens, MAGNT Cr015605, Iron Ore Wharf, Darwin Harbour (12.4725'S 130.8428'E), wharf pylon scraping, 28 March 1999, coll: MAGNT / CSIRO Survey Team; paratypes 5 specimens, MAGNT Cr015623, Fort Hill Wharf , Darwin Harbour (12.4715'S 130.8467'E), wharf pylon scrapings, 27 March 1999, coll: MAGNT / CSIRO Survey Team; paratypes 4 specimens, MAGNT Cr015634, Fort Hill Wharf, Darwin Harbour (12.4715'S 130.8467'E), wharf pylon scrapings, 27 March 1999, coll: MAGNT / CSIRO Survey Team; paratypes 4 specimens, MAGNT Cr015667, Iron Ore Wharf, Darwin Harbour (12.4725'S 130.8428'E), wharf pylon scrapings, 28 March 1999, coll: MAGNT / CSIRO Survey Team.

Additional material examined. 3 specimens, MAGNT Cr 015552, Fort Hill Wharf, Darwin Harbour (12.4715'S

130.8467'E), wharf pylon scrapings, 27 March 1999 coll: MAGNT / CSIRO Survey Team; 14 specimens, MAGNT Cr 015683, East Arm Port, Darwin Harbour (12.4918'S 130.8831'E), wharf pylon scrapings, 20 August 1998, coll: MAGNT / CSIRO Survey Team ; 2 specimens, MAGNT Cr 015693, Near Stokes Hill Wharf, Darwin Harbour (12.47'S 130.8483'E), wharf pylon scrapings, 18 August 1998, coll: MAGNT / CSIRO Survey Team ; 3 specimens, MAGNT Cr 015918, Channel Island, Middle Arm , Darwin Harbour (12.55'S 130.8667'E), intertidal algae and rubble, 14 November 1985, coll: C. Watson ; 11 specimens, AM P.78313, west end of East Point, north end of Fannie Bay, Darwin (11°24'00"S 130°48'30"E), 8–10 m, on Gorgonian Echinogorgia sp., 26 October 1982, coll. J. K. Lowry (NT 92) ; 1 male, 6.2 mm, dissected, 4 slides, MAGNT Cr 017410, Port Essington (11.3333'S 132.1667'E), March 1984. coll: NT Fisheries ; 1 female, 4.7 mm, dissected, 1 slide, MAGNT Cr 017409, Port Essington (11.3333'S 132.1667'E), March 1984, coll: NT Fisheries ; 1 male, SEM pin mount, AM P.85667, Port Essington (11.3333'S 132.1667'E) ; 1 male, 5.2 mm, SEM pin mount, AM P. 87035, Port Essington (11.3333'S 132.1667'E) ; 8 specimens (1 male, 5 female and 2 juvenile), Cr 015841, Port Essington (11.3333'S 132.1667'E), March 1984, coll: NT Fisheries ; 7 specimens (1 male and 6 female), Cr 015855, Port Essington (11.3333'S 132.1667'E) ; 4 female specimens, MAGNT Cr 015837, Perkins Wharf, Gove Harbour , Gulf of Carpentaria (12.1938'S 136.72'E), 0.5 m, 7 June 2001, coll. K. Neil & party ( JCU /CRC Reef ) (A571 GB7) ; 1 specimen, MAGNT Cr 015825, Cargo Wharf, Gove Harbour , Gulf of Carpentaria (12.2042'S 136.6808'E), 8 June 2001 coll. K. Neil & party ( JCU /CRC Reef ) (A695 GD0) .

Diagnosis. Head with weak hump; lateral cephalic lobe subquadrate. Gnathopod 1 coxa smaller than coxa 2, as broad as long, anteroventral corner produced anteriorly, apically subacute. Gnathopod 2 basis 1.5 times as long as broad, with long slender setae; carpus indistinct, fused with propodus; propodus subovate, palm 3⁄4 the length of the propodus, palm with 2 teeth, defined by tooth, without robust setae; dactylus closing short of palm end. Pereonite 3 dorsal carina narrow, produced evenly, subtriangular, apically subacute. Pereonite 4 dorsal carina narrow, produced evenly, subtriangular, apically rounded. Pereonite 5 dorsal carina narrow, produced evenly, subtriangular, apically subacute. Pereonite 6 dorsal carina broad, produced posteriorly, subtriangular, apically acute. Pereonite 7 dorsal carina broad, produced posteriorly, subtriangular, apically rounded. Pleonite 1 dorsal carina broad, produced posteriorly, subtriangular, apically subacute. Pleonite 2 dorsal carina broad, produced posteriorly, broadly rounded.

Description. Based on holotype male, 4.4 mm. MAGNT Cr017407. Body cuticle dorsally smooth, with posterior dorsal carina, laterally smooth. Head with weak hump; rostrum short, about one tenth of head length; eyes greatly bulging; lateral cephalic lobe subquadrate; anteroventral corner subquadrate. Mandible accessory setal row with 3 setae. Maxilla 1 palp distal margin with 5 robust setae.

Gnathopod 1 coxa smaller than coxa 2, as broad as long, anteroventral corner produced anteriorly, apically subacute; basis 2.5 times as long as broad, without anterodistal setae; carpus subtriangular, 1.8 times as long as broad; propodus subtriangular, anterior margin with clusters of long slender setae, palm margin smooth with 2 long robust setae near corner of palm; dactylus posterior margin with serrate teeth, cuticle surface with raised serrations. Gnathopod 2 basis 1.5 times as long as broad, anterodistal corner with produced subacute lobes with long slender setae; merus posterior margin with narrow produced lobe, lobe as long as broad, posterior margin apically acute; carpus indistinct, fused with propodus; propodus subovate, length 1.9 times width, anterior margin with clusters of short robust setae, medial surface with dense plumose setae, palm acute, straight, 3⁄4 the length of the propodus, with broad, well developed distal shelf, shelf margin strongly crenulate, palm with 2 teeth, defined by tooth, without robust setae; dactylus closing short of palm end. Pereonite 3 dorsal carina narrow, produced evenly, subtriangular, apically subacute. Pereonite 4 dorsal carina narrow, produced evenly, subtriangular, apically rounded. Pereonite 5 dorsal carina narrow, produced evenly, subtriangular, apically subacute. Pereonite 6 dorsal carina broad, produced posteriorly, subtriangular, apically acute. Pereonite 7 dorsal carina broad, produced posteriorly, subtriangular, apically rounded.

Pleonite 1 dorsal carina broad, produced posteriorly, subtriangular, apically subacute; epimeron 1 posteroventral corner rounded. Pleonite 2 dorsal carina broad, produced posteriorly, broadly rounded; epimera 2–3 posteroventral corner subquadrate. Urosomite 1 length twice as long as broad. Uropod 1 biramus, peduncle ventromedial spine absent; inner ramus 1.2 times peduncule length. Uropod 2 biramus, peduncle ventromedial spine absent; outer ramus about half the length of inner ramus. Uropod 3 uniramus; rami without setae. Telson dorsal lobe with 2 apical setae, lower margin without lateral or apical setae.

Female (sexually dimorphic characters) based on paratype female, 4.7 mm. MAGNT Cr014708. Gnathopod 2 basis 2 times long as broad; anterodistal corner subquadrate, without setae; merus posterior margin with broad lobe, lobe 0.9 times as long as broad, with a few slender setae; carpus free, distinct from propodus; propodus length 1.2 times width, anterior margin with clusters of long slender setae, palm conveX without distal shelf, defined by corner with 2 robust setae.

Variation. Podocerus ferreus sp. nov. has variable dorsal carinae with either well or poorly developed processes seen for both male and female specimens. The development of carina is not related to growth stage. Both carina forms are recorded in the same sample from numerous locations.

Remarks. The variable dorsal carina in Podocerus ferreus sp. nov. is similar to the intra-specific variation known for P. oronotes sp. nov. and P. lobatus (of Pirlot, 1938) where individuals are known with either acute or rounded carina.

Podocerus ferreus sp. nov. has the male gnathopod 2 propodus palm with a well-developed shelf and three teeth, similar to P. talegus levuensis Myers, 1985 , P. ulreungensis Kim & Kim, 1991 and P. wanganui J. L. Barnard, 1972 . However, uropod 1 is without a ventromedial spur in P. ferreus sp. nov., differentiating it from P. wanganui . In P. ferreus sp. nov. the cephalic lobe is subquadrate while in P. ulreungensis it is acute. The dorsum overall appearance is smooth in P. ferreus sp. nov. and with slight ridging in P. ulreungensis . In P. ferreus sp. nov. gnathopod 1 propodus is recotolinear in shape while spheroid and subtriangular in P. talegus levuensis and P. wanganui , respectively.

Distribution. Australia. Northern Territory: Port Essington, Darwin Harbour, Gove Harbour (currently study).

Figures

Figure 8. Podocerus ferreus sp. nov. paratype male, 4.8 mm, AM P.85670, Darwin Harbour, Northern Territory. SEM photographs: (A) whole animal lateral view (scale 200 µm); (B) head lateral view (scale 100 µm); (C) head dorsal view (scale 200 µm) (D) gnathopod 2 propodus palm plumose setae (scale 20 µm) and (E) whole animal dorsal view (scale 200 µm). Male, 5.2 mm, AM P.87035, (F) whole animal lateral view (scale 200 µm); and (G) whole animal dorsal view (scale 200 µm).

Figure 9. Podocerus ferreus sp. nov. holotype male, 4.4 mm, MAGNT Cr017407, and paratype female, 4.7 mm, MAGNT Cr017408, Darwin Harbour, Northern Territory (scale 0.1 mm).