Dactylopleustes echinoides Bousfield and Hendrycks, 1995

Tomikawa, Ko, Hendrycks, Ed A. & Mawatari, Shunsuke F., 2004, A new species of the genus Dactylopleustes (Crustacea: Amphipoda: Pleustidae) from Japan, with a partial redescription of D. echinoides Bousfield and Hendrycks, 1995, Zootaxa 674, pp. 1-14 : 11-12

Dactylopleustes echinoides Bousfield and Hendrycks, 1995

( Figure 6 )

Dactylopleustes echinoides Bousfield and Hendrycks, 1995: 121 –122, figure 40.

Type material

Holotype: ovigerous female, 3.3 mm (slide mount), CMNC 1995­0079, Station N16, British Columbia, Johnstone Strait, Port Neville, 50°29'N, 126°05'W, 17 July 1959, collector E. L. Bousfield. Paratypes: 2 ovigerous females, one juvenile female, one juvenile (undissected), CMNC 1995­0080, same data as holotype.

Other material

Three females, 3–3.5 mm, taken from the green sea urchin Strongylocentrotus droebachiensis , dredged from about 91 m depth from San Juan Channel, near Friday Harbor Lab, Washington, May 2000.

Redescription

Antennae 1–2: flagellum with four–six and four–five articles respectively. Maxilla 2: outer plate with six stout, spine­like setae apically. Maxilliped: inner plate with two­three apical spines.

Pereopod 5: propodus, anterior margin with 11 short spines, length 2.7 times width; dactylus, anterior margin with distinct teeth. Pereopod 6: as for pereopod 5 except; propodus, anterior margin with seven short spines, length 2.9 times width. Pereopod 7: as for pereopod 6 except; propodus, anterior margin with eight short spines, length 2.8 times width.

Uropod 1: peduncle spinose, length 1.1 times inner ramus, with eight dorsolateral and 4 dorsomedial spines; outer ramus length 0.95 times inner ramus, with seven dorsolateral and four dorsomedial marginal spines; inner ramus with four dorsolateral and seven dorsomedial marginal spines. Uropod 2: peduncle length 0.9 times inner ramus, with one dorsolateral, one apicodorsal and one apicomedial spine; outer ramus length 0.8 times inner ramus, with six dorsolateral and one dorsomedial marginal spine; inner ramus with three dorsolateral and five dorsomedial marginal spines.

Remarks

The type specimen of Dactylopleustes echinoides was examined and compared with the material at hand. Supplemental drawings are presented ( Fig 6 ) to show characters which differ from D. yoshimurai .

There are a few discrepancies noted in the description of this species by Bousfield and Hendrycks (1995). They described the outer plate of maxilla 2 as having 12 apical spines, but their figure only shows six spines. After examining the holotype, we have found that the outer plate indeed has only six spine­like setae apically, as was shown correctly in figure 40. The maxilliped inner plate was figured as having no apical spines, but the description mentions three. After a detailed examination, it was found to have very minute apical spines, with two on one side and three on the other. The counts of anteromarginal spines on the propodus of pereopods 5–7 were not specified by Bousfield and Hendrycks (1995), but these characters have been found to be useful in distinguishing D. echinoides from D. yoshimurai .

See remarks section under Dactylopleustes yoshimurai for relationship to this species.

Figures

FIGURE 6. Dactylopleustes echinoides Bousfield and Hendrycks, 1995, holotype female, 3.3 mm (CMNC 1995 ­ 0079). Scale bars = 0.1 mm unless indicated otherwise.