Comprehensive Description

provided by Smithsonian Contributions to Zoology
Lubbockia forcipula

MATERIAL STUDIED (Tables 1, 2).—NE PACIFIC: 1 female, holotype, 1.03 mm, NP 11, USNM 168492. ANTARCTIC OCEAN: 2 females, 1.08, 1.12 mm, AA 42.

FEMALE.—Length about 1.08 mm. Prosome (Figure 7a,b) 1.2 times the length of urosome.

Pediger 5 with transverse sclerotized ridge dorsoposteriorly. Genital segment with areas of external genital apparatus on anteriolateral third of segment; each area with a setule. Genital segment and each postgenital segment with delicate minute spinules on posteroventral margin. Uropod about 2/3 length of genital segment, posteriorly dilated over base of dorsal seta; dorsal, innermost, and outer long terminal setae nearly as long as inner long terminal seta.

Rostrum with thickened posteroventral margin slightly depressed and indented as shown in ventral view of cephalosome (Figure 7c).

Antenna 1 (Figure 7c) and antenna 2 (Figure 7c,d) with armature similar in number to that of L. carinata.

Labrum (Figure 7e) with free margin divided into 2 posteroventral lobes, each with a subapical cluster of setules; complex pattern of layers of tissues with hyaline setules inserted on under surfaces.

Mandible (Figure 7f), maxilla 1 (Figure 7g), and maxilla 2 (Figure 7h) with armature similar in number to that of L. carinata.

Maxilliped (Figure 7i) 4-segmented, cheliform. Second segment beaklike, projecting beyond and somewhat enclosing the tip of short terminal claw, the complex forming a short, strong pincer.

Legs 1–4 (Figure 8a–d) with armature similar in number to that of L. carinata except for the addition of an inner spine on leg 1 basis.

Leg 5 (Figure 7a) similar in general form to that of L. carinata, including seta on body near leg.

Leg 6 probably represented by short, hyaline setule in area of external genital apparatus.


ETYMOLOGY.—The specific name, from the Latin forcipula (nippers, tongs), refers to the appearance of the maxilliped in the female.

DISTRIBUTION.—Northeast Pacific and Antarctic Ocean (Tables 1, 2).

Lubbockia wilsonae Heron and Damkaer, 1969

Lubbockia aculeata.—Vervoort, 1951:151; 1957:148. [Not L. aculeata Giesbrecht, 1891.]

Lubbockia wilsonae Heron and Damkaer, 1969:9–15, figs. 11–19.

The original description of Lubbockia wilsonae was based on 2 females (2.70, 2.75 mm) from the Gulf of Alaska. Additional specimens of both sexes from the northeast Pacific have made it possible to describe the male and amend the original description of the female.

MATERIAL STUDIED (Tables 1, 2).—NE PACIFIC; Prince William Sound, Alaska: 3 females, 2.80–2.98 mm, NP 1. Near the Canadian weathership sta P: 6 females, 2.64–2.88 mm, NP 38, 39; 3 males, 1.96–2.08 mm, NP 38, USNM 168503, 168504; 8 juveniles, stage V, NP 38, 39; 2 juveniles, stage IV, both 1.48 mm, NP 39; 2 juveniles, stage III, 0.97, 1.06 mm, NP 7, 4 (frequency of sex and stage categories by depth for samples NP 38, 39 shown in accompanying tabulation). ANTARCTIC OCEAN: 3 males, 2.42–2.44 mm, AA 42.

FEMALE.—Rostrum (Figure 9a) rounded posteriorly. Antenna 1 in all Lubbockia species appears to be fundamentally 7-segmented; segment 3 often with incomplete or no suture separating 4. Female Lubbockia specimens have been described as having from 4 or 5 to 7 segments in antenna 1; some sutures are incomplete on inner surface, while articulation is usually more distinct on outer surface. Lubbockia wilsonae female antenna 1 is 7-segmented (rather than 6) with segments 3–4 partially or completely fused. Armature should be corrected from original description to 4, 6 + 1 esthete + 1 spinule, 2 spines, 4, 3 + 1 esthete, 2 + 1 esthete, 5 + 2 esthetes (1 seta, about equal to combined length of segments 5–7, in place of 2 short setae shown on figure 14 of Heron and Damkaer, 1969).

Maxilla 1 (Figure 9b) bilobed; inner lobe with 2 elements and short hyaline setules; 3 elements on larger lobe.

MALE.—Length about 2.01 mm (NE Pacific) to 2.43 mm (Antarctic). Body (Figure 9c,d) slender, with prosome to urosome ratio and relative lengths of urosomal segments similar to female. Prosome with conspicuous sensilla, gland vents, and minute spinules. Urosomal segments covered with minute spinules, somewhat larger on most ventral surfaces; posteroventral margins with spinule patterns similar to those of female. Genital segment (Figure 9e) with conspicuous spinules on ventral surface. Relative lengths of uropodal setae as in female.

Rostrum (Figure 9f) more tapered posteroventrally than in female.

Antenna 1 distinctly segmented only between segments 4 and 5 and outer surface of 1 and 2. Armature similar in number to that of female except for additions of esthete on segment 2 and 2 esthetes on segment 4. All esthetes, except 1 each on segments corresponding to segments 2 and 7 (labeled “x” in Figure 9g) longer and of a different structure than those of female. Terminal esthete (labeled “y” in Figure 9g) with broad base and wide setalike rib supporting entire length; nearly reaches urosome segment 3. The 5 other esthetes extend from a short base (labeled “z” in Figure 9g) and also have a supporting rib.

Antenna 2 (Figure 9h) third segment sexually dimorphic; 3 terminal claws of female modified to 3 short setae, and 1 seta modified to long lash; 2 clusters of long setules on inner surface.

Labrum with hood extending to cover vertex between the 2 posteroventral lobes.

Mandible, maxilla 1, and maxilla 2 degenerate, variable between specimens and right and left.

Maxilliped (Figure 9i) with outer surfaces of segments 1 and 2 rugose; second segment with inner row of setules; cluster of long, delicate setules on inner distal surface; terminal claw undulant.

Swimming legs and leg 5 as in female.

Leg 6 probably represented by posteroventral flap on genital segment, bearing 2 elements.

STAGE V.—Female (Figure 9j) 1.98 mm, male (Figure 9k) 1.75 mm, with 5 segments and uropod in urosome; leg 5 well developed. Male with a faint sclerotized ventral line on genital segment in area of adult anterior margin of posteroventral flap.

STAGE IV.—Length 1.48 mm, with 4 segments and uropods in urosome; leg 5 small with 2 spines; inner spine reaching beyond posterior edge of next segment.

STAGE III.—Two specimens, 0.97, 1.06 mm, with 5 segments in the prosome and 3 segments and uropods in urosome (Figure 9l); leg 5 represented by 1 spine. Antenna 2 with 6 elements similar to that in adult female. Maxilliped with relative size similar to that in adult female, 2 small triangular spines on second segment and small hyaline spinules on terminal claw.
bibliographic citation
Heron, Gayle A. and Damkaer, David M. 1978. "Seven Lubbockia species (Copepoda: cyclopoida) from the plankton of the northeast Pacific, with a review of the genus." Smithsonian Contributions to Zoology. 1-36. https://doi.org/10.5479/si.00810282.267