Prachynella oculata, Lowry & Stoddart, 2012

Lowry, J. K. & Stoddart, H. E., 2012, The Pachynidae fam. nov. (Crustacea: Amphipoda: Lysianassoidea) 3246, Zootaxa 3246 (1), pp. 1-69 : 51-52

Prachynella oculata sp. nov.

( Fig. 35 )

Prachynella lodo . — J.L. Barnard, 1964: 233, fig. 7 (in part, not the designated holotype). ―J.L. Barnard, 1966a: 70 (in part). ―J.L. Barnard, 1966b: 26 (in part). ―J.L. Barnard, 1967: fig. 29 and possibly figs 30h–k.

Type material. HOLOTYPE, female, 6.2 mm, LACM, 9 miles, 185° T. from Point Loma Light, California, USA, 32°31'0''N 117°15'20''W, red sand, 14 August 1957, Velero IV stn 5193 (specimen illustrated in J.L. Barnard, 1964: fig. 7 and J.L. Barnard, 1967: fig. 29 as P. lodo ). PARATYPE, male, 4.5 mm, LACM, 10 miles south of Point Loma, southern California, USA, 32°30'00"N 117°13'15"W, 41 m, coarse red (rust-coloured) sand, 26 March 1957, Velero IV stn 4910.

Additional material examined. (all previously identified by J.L. Barnard as P. lodo ). 1 specimen, LACM, 6 miles, 278 ° T. from Hyperion Stack , California, USA, 33°56'37''N 118°33'2''W, Hayward grab, 08:50–08:57 hrs, 20 June 1956, Velero IV stn 4318 ; 1 specimen, LACM, 2.7 miles, 319 ° T. from Point Loma Light , California, USA, 32°42'0''N 117°16'30''W, medium to coarse shelly sand, Hayward grab, 09:52–10:19 hrs, 8 December 1956, Velero IV stn 4755 ; 2 specimens, LACM, 4 miles, 148 ° T. from Santa Barbara Point Light , California, USA, 34°20'20''N 119°40'40''W, 68 m, green medium sand, Hayward grab, 09:49–10:06 hrs, 3 July 1957, Velero IV stn 5168 ; 1 specimen, LACM, 7.8 miles, 158 ° T. from Point Loma Light , California, USA, 32°32'45''N 117°11'0''W, medium gray sand, 10:21–10:47 hrs, 14 August 1957, Velero IV stn 5189 ; 1 specimen, LACM, 7.45 miles, 156.5 ° T. from Point Loma Light , California, USA, 32°33'10''N 117°10'57"W, medium gray sand, 09:48–10:00 hrs, 18 February 1958, Velero IV stn 5606 ; 1 specimen, LACM, 4.55 miles, 273 ° T. from Hyperion Stack , Santa Monica Bay, California, USA, 33°55'54''N 118°31'16''W, 57 m, dark olive green silty sand, 10:45–10:56 hrs, 18 April 1958, Velero IV stn 5711 ; 1 specimen, LACM, 4.4 miles, 312 ° T. from Point Pinos Light , Monterey Bay, California, USA, 36°40'56'' 122°0'0'', Hayward grab, glauconitic sand, 10:20–10:28 hrs, 10 February 1959, Velero IV stn 6471 .

Type locality. 9 miles, 185° T. from Point Loma Light , California, USA, 32°31'0''N 117°15'20''W .

Etymology. Named for J.L. Barnard’s description of the material as “the oculate form”.

Diagnostic description. Head lateral cephalic lobe large, broadly rounded; ventral margin curved. Antenna 1 peduncular article 1 with posterodistal spine; accessory flagellum 2-articulate, article 1 short; flagellum with strong 1-field callynophore in female and male. Mandible lacinia mobilis a simple robust seta; accessory setal row present on both sides, not on raised setose ridge; molar absent; palp attached distally; palp article 2 broad, as long as article 3; article 3 with subparallel margins. Maxilla 1 outer plate with 10 setal-teeth in 7/3 arrangement, outer row setal-teeth with medial cusps. Maxilliped inner plate small; outer plate large; palp 3-articulate (articles 1 and 2 fused). Gnathopod 1 chelate; ischium smaller than propodus, not swollen posteroproximally; carpus extremely compressed; propodus length about 1.8 × breadth, posterior margin well developed, palm with produced corner, pollex length about 1.6 × breadth, corner of palm with complex robust seta; dactylus reaching to corner of palm. Gnathopod 2 palm minute, obtuse. Pereonite 4 without dorsal spines. Pereonite 5 with 1 rounded dorsal spine. Pereopod 5 basis subovate; merus with posteroproximal shoulder. Pereopod 6 basis with posteroventral lobe produced beyond ischium; merus longer than broad, with posteroproximal shoulder. Pereopod 7 basis subrectangular with posterior margin weakly dentate. Oostegites from gnathopod 2 to pereopod 5. Epimeron 3 posterior margin without projections, posteroventral corner broadly rounded. Uropod 3 biramous, inner ramus extending more than halfway along outer ramus but not reaching base of article 2. Telson shorter than broad, entire.

Remarks. See remarks under P. lodo . Although not shown in J.L. Barnard’s figures, the palm of gnathopod 1 is defined by a complex robust seta.

Distribution. Southern California, USA, eastern North Pacific Ocean; 40–140 m depth.

Figures

FIGURE 35. Prachynella oculata, sp. nov. Holotype female, 6.2 mm, LACM, southern California, USA. Scales for MD, MX1 represent 0.1 mm, remainder represent 0.2 mm.