Chlamydopleon aculeatum Ortmann 1893

Chlamydopleon aculeatum Ortmann, 1893

(Fig. 1 A–H)

Chlamydopleon aculeatum Ortmann, 1893: 25, pl. 2 fig. 1.

Material examined. Type material: Lectotype (by present designation), 1 subterminal male 6.2 mm, ZSMA 20071609, mouth of the Tocantins River (Brazil), 24 Sept. 1889, leg. Plankton-Expedition der Humboldt-Stiftung; labeled as Chlamydopleon aculeatum, Gastrosaccus aculeatus, and Bowmaniella dissimilis by unknown previous workers.— Paralectotype, 1 ad. fem. 6.4 mm, ZSMA 20071610, same data as lectotype.

Diagnosis. All features of the above generic definition. Rostrum triangular with blunt tip, short, not reaching to half the length of eyestalks (when extended anteriorly; Fig. 1 A). Postero-dorsal margin of carapace with three sinusoid lobes; the two submedian lobes are less than twice the length of the median lobe (Fig. 1 B). Exopod of third pleopod in the subterminal male with two setae on third segment (Fig. 1 D). Apical cleft is 7–12 % telson length.

Revised description. Cornea larger in male than in female. Median segment of antennular peduncle with two spines on outer margin, terminal segment with one small spine near its outer distal corner (Fig. 1 A). Antennal scale extends to the end of the second segment of antennular peduncle; its tip extends slightly beyond the terminal tooth on its outer margin (Fig. 1 A). Terminal margin of the carapace appears smooth at 100 x magnification. Basal plate of all thoracic exopods with strong lateral expansion armed with acute tooth (spiniform extension) in subterminal to terminal position on outer margin. This tooth is largest in intermediate exopods. Flagellum of first to eighth exopods with 10, 11, 11, 11–12, 11–12, 11–12, 12–13, and 11 segments, respectively. Carpopropodus of third to eighth thoracic endopods with 4–6, 4–6, 5–6, 6–8, 6–11, and 6–10 segments, respectively; dactylus without claw. Penis large and very stout, postero-ventrally widened by a hyaline membrane (Fig. 1 C). Exopods of the first to fifth pleopods of the subterminal male with 6, 7, 4, 4, and 6 segments, respectively; tip of third exopod with long, apically widened inner stylet; this stylet has a roughly transverse end, apart from a small spiniform projection of its outer, distal corner; outer branch of this exopod with a small, apically directed ventral tooth (Fig. 1 D). Endopod of uropods with 6–7 ventrally projecting spines along inner margin between statocyst and shortly below tip (Fig. 1 E, F). The length of these spines appears perspectively shortened in ventral view (Fig. 1 F). Telson with 6–7 spines on each lateral margin, not counting the pair of large (sub)apical spines present on each latero-terminal lobe (Fig. 1 G). Cleft with 24–28 laminae (Fig. 1 G, H).

Etymology. The Latin adjective ‘ aculeatus ’ means ‘spiny’, ‘aculeate’.

Type locality. Mouth of the Tocantins River (Brazil). Additional data about the type locality were derived from the expedition log in Hensen (1895): coordinates 0.7°S, 48.2°W; water parameters measured on 24 Sept. 1889 were 28.0°C and salinity of S = 11.4. So far, there is no evidence that the species was sampled elsewhere as well.

Chlamydopleon dissimile (Coifmann, 1937), new combination (Fig. 1 J–L)

Gastrosaccus dissimilis Coifmann, 1937: 5, figs. 2, 3.

Bowmaniella (Coifmanniella) dissimilis.— Bǎcescu, 1968: 363, fig. 4.

Bowmaniella dissimilis.— Brattegard, 1970: 11, fig. 2; Heard & Price, 2006: 7, figs. 1, 2C–D, 4A, 5A, 6A–B, 8F; Innocenti, 2006: 21.

Bowmaniella (Coifmanniella) brasiliensis Bǎcescu, 1968: 363, figs. 5, 6.

Bowmaniella brasiliensis.— Borzone et al., 2007: 945.

Bowmaniella floridana Holmquist, 1975: 68.

Material examined. Type material: Lectotype (designated by R.W. Heard and W.W. Price), 1 subterminal male 8.1 mm, MZS 2740, coast of Brazil (15°S, 38°W), 31 July 1882, leg. G. Chierchia, R/V «Vettor Pisani», previous det. I. Coifmann as Gastrosaccus dissimilis n.sp., rev. R.W. Heard and W.W. Price as Bowmaniella dissimilis.— Paralectotypes, 2 ad. fem. 9.4–10.3 mm, 1 subad. fem. 7.9 mm, 1 imm. male 8.2 mm, 2 juv., MZS 2741, same data as lectotype.

Additional material [square brackets indicate geographical data estimated by the present author]: 1 subterm. male ca. 7.3 mm, 1 ad. fem. 10.1 mm, MNB 9734, Brazil, Lage de Santos [= Laje de Santos, 24.25°S, 46.17°W, small island 36 km off the city of Santos], St. 4., 2. M., 18 May 1961, leg. Plinio Soares, MNC, epibenthic sled (draga circular); material accompanied by 1 ad. fem. 8.7 mm plus 2 damaged specimens of Coifmanniella mexicana (W.M. Tattersall, 1951).—1 term. male 9.9 mm, 4 ad. fem. 10.8–11.8 mm, UT, Costa Rica, Caribbean coast, Limón Province, Manzanillo [9.637°N, 82.653°W], 17 Nov. 1999, leg. R.W. Heard, beach, intertidal, depth 1 m, epibenthic sled.—1 term. male 8.7 mm, 1 subterm. male 7.3 mm, 2 ad. fem. 10.7–11.1 mm, UT, same province, Punta Vargas [9.655°N, 82.759°W], St. 1, 18 Nov. 1999, leg. R.W. Heard, epibenthic sled.—2 term. males 8.3–10.0 mm, 3 subterm. males 6.7–8.8 mm, 3 ad. fem. 8.1–8.4 mm, UT, Tobago, Bloody Bay [11.303°N, 60.631°W], St. 4, 4 April 1992, leg. R.W. Heard, epibenthic sled.— 2 ad. fem. 7.5–7.6 mm, 1 imm. male, UT, Mexico, Veracruz, Tuxpan, 21.00°N, 97.35°W, 24 May 1973, leg. W.W. Price, depth 1–1.5 m, T = 25°C, S = 37, beam trawl.—1 subterm. male 6.5 mm, 7 ad. fem. 6.3–8.9 mm, 8 subad. fem. 5.1–6.5 mm, 43 imm., 15 juv., GAM MYS 285, Cuba [23.15°N, 82.37°W], 24 May 1969. — 1 ad. fem. 10.7 mm, 1 imm. fem., UT, Texas, Port Isabel Beach, 26.17°N, 97.17°W, 24 May 1973, leg. W.W. Price, beam trawl.—1 subterm. male 7.0 mm, 1 ad. fem. 8.1 mm, UT, Texas, Lavaca Bay [28.70°N, 96.61°W], LB-7-TL, 8 June 1971, leg. Don Harper, T = 28°C, S = 29, trawl.—1 subterm. male 8.8 mm, UT, same bay, LB-5-TL, 4 Dec. 1971, leg. D. Harper, T = 21°C, S = 22, trawl.—1 subterm. male 10.2 mm, UT, Texas, Galveston Bay [29.6°N, 94.9°W], St. 20, Jan. 1972, leg. W.W. Price, sandy (high energy) beach, depth 1–1.5 m, T = 23.2°C, S = 15.6, beam trawl.—5 term. males 6.6–7.8 mm, 9 subterm. males 6.4–7.7 mm, 6 ad. fem. 8.1–8.9 mm, UT, Florida, Manatee River (empties into Tampa Bay), St. 14M2B, 27.5233°N, 82.4285°W, 10 June 1998, leg. W.W. Price, depth 1–1.5 m, T = 23.2°C, S = 4.25, night plankton tow.—4 term. males 7.9–8.4 mm, 6 subterm. males 7.4–9.3 mm, 5 ad. fem. 9.4–10.9 mm, UT, Florida, Tampa Bay, Fl. Courtney Campbell Causeway, southeast side [27.969°N, 82.610°W], 3 March 1987, leg. W.W. Price, depth 1–1.5 m, S = 18, epibenthic sled.—1 term. male 7.7 mm, 4 subterm. males 7.2–7.7 mm, 8 ad. fem. 8.8–10.0 mm, 7 subad. fem. 5.9–7.5 mm, 70 imm., 7 juv., SERTC S1234, Georgia, Savannah, Little Tybee Island, 31.9733°N, 80.8567°W, 10 June 1991, leg. R.W. Heard and D. Roccatagliata, sandy beach, intertidal, swash zone.—2 term. males 8.4–8.6 mm, 3 subterm. males 7.8–8.6 mm, 2 ad. fem. 9.6–10.2 mm, 5 subad. fem. 6.6–9.0 mm, 12 imm., 22 juv., SERTC S1235, South Carolina, Clambank Creek, North Inlet, 33.3347°N, 79.1888°W, 2 Nov. 1979, leg. D.M. Allen, depth 10.2 m, bottom sled. —1 subterm. male 7.6 mm, GAM MYS 277, North Carolina, platform off Beaufort [34.33°N, 75.95°W], 24 Nov. 1965, leg. Duke Marine Lab.

Revised diagnosis. All features of the above generic definition. Rostrum acute, extending to 10–80 % eye length (Fig. 2; including cornea; with eye oriented anteriorly). Postero-dorsal margin of carapace with a subtriangular to triangular median lobe and two sinusoid to claw-shaped submedian lobes (Fig. 3); the submedian lobes are 2–3 times the length of the median lobe (Fig. 1 J). Exopod of third pleopod in the subterminal male without setae on third segment (Fig. 1 K). The same exopod in the terminal male without bow, inner branch with inner stylet reaching to less than half length of distal segment. Apical cleft is 10–12 % telson length.

Description (Brazilian material only). Cornea larger in subterminal and larger still in the terminal male (not so in immature male) compared to subadult and adult females; no such differences were found for eyestalk length. Rostrum shorter than eyestalk (Brazil pops. in Fig. 2). Terminal margin of carapace with variable number of fine denticles, in highest density on terminal edge of lobes; visible at ≥ 100 x magnification (Fig. 3). Median segment of antennular peduncle with two spines on outer margin, terminal segment with one small spine near its outer distal corner. Antennal scale extends to end of second segment of antennular peduncle. Its tip extends slightly beyond the terminal tooth on its outer margin or ends at about same height (c.f. below). Basal plate of all thoracic exopods with strong lateral expansion armed with acute tooth in subterminal to terminal position on outer margin. This tooth is largest in intermediate exopods. Flagellum of first to eighth exopods with 9–11, 10–11, 10–12, 11–13, 11–13, 11–14, 11–13, and 10–13 segments, respectively. Carpopropodus of third to eighth thoracic endopods with 5–7, 5–10, 6–11, 8–13, 9–13, and 9–13 segments, respectively; dactylus without claw. Penis large and very stout, posteriorly widened by a hyaline membrane. Exopods of first to fifth pleopods of subterminal male with 5–6, 7, 4, 4–5, and 5–6 segments, respectively; third exopod with long, apically widened inner stylet; this stylet ends in a roughly transverse (Fig. 1 K) to oblique terminal margin; blade of exopod subequal to distinctly shorter (Fig. 1 K) than outer branch; this branch with tooth-like (Fig. 1 K) to blunt ventral process. Endopod of uropods with 6–8 spines in roughly continuous series along inner margin between statocyst and shortly below tip. Telson with 6–7 spines on each lateral margin, not counting the pair of large (sub)apical spines present on each lateroterminal lobe. Cleft with 25–29 laminae.

Etymology and spelling. With the Latin adjective ‘ dissimilis ’, Coifmann (1937) emphasized the strong dissimilarity with the remaining Gastrosaccus species acknowledged by her. As a mandatory change the ending of the species name was adapted here to the neutral gender of Chlamydopleon, yielding dissimile (new spelling).

Type locality. Coast of Brazil between Pernambuco and Rio de Janeiro (15°S, 38°W).

Distribution. Temperate to tropical, estuarine and marine coastal waters of the West Atlantic, between 25°S and 39°N.

Regional variability. Body size (n = 114). Average lengths, 9.23 ± 1.31 mm (± S.D.; n = 44) in adult females, 6.85 ± 1.17 mm (n = 21) in subadult females, 8.23 ± 0.88 mm (n = 16) in terminal males, and 7.48 ± 0.78 mm (n = 33) in subterminal males. CATREG was applied on body size as a dependent variable (R2 = 0.757) and gave—in order of decreasing Pratt coefficients of importance—stage, sampling locality, and sex as significant predictors, but not so latitude.

Antennal scale (n = 114). The terminal tooth extended almost up to (Bǎcescu, 1968: fig. 6J) or slightly beyond the tip of the antennal scale in specimens from Brazil, Central America (Costa Rica, Tobago, Veracruz), and Cuba. The average spine length was longer and showed greater inter-individual variability (Brattegard, 1970: fig. 2A; Stuck et al., 1979: fig. 2C, D) in specimens from North America (Texas, Florida, Georgia, South Carolina).

Carapace (n = 114). The rostrum of specimens from the locations south of 22°N, namely in Brazil and Central America, was always shorter than the eyestalks (Fig. 2). A greater inter-individual variability was found in the more northern regions, namely in Cuba and North America. Here the rostrums measured 50–180% eyestalk length. CATREG was applied on the quotient of rostrum length by eyestalk length (Fig. 2) as a dependent variable (R2 = 0.316), yielding latitude as a significant determinant, but not sampling locality, sex, stage, and body size.

The submedian lobes on the postero-dorsal margin of the carapace showed a broad variation between sinusoid and claw-shaped (Figs. 1 J, 3). Only (near) sinusoid lobes were found in Brazil, subtriangular to (near) claw-shaped lobes in Central America, sinusoid to subtriangular in Cuba, and the greatest variability with (near) sinusoid to (near) claw-shaped lobes in North America. CATREG was applied on the code for lobe shape (Fig. 3) as a dependent variable (R2 = 0.554), yielding sampling locality as a significant determinant, but not latitude, sex, stage, and body size.

Third pleopod in the subterminal male (n = 33). A pair of setae as shown in Fig. 1 D for C. aculeatum was never found on the third segment of the exopod. An acutely pointed ventral process (Fig. 1 K) on this exopod was found only in the lectotype of C. dissimile and in one specimen (7.3 mm) from Costa Rica. In the remaining subterminal males examined, this process was represented by a distinctly projecting protuberance with blunt tip or only by a small hump (Fig. 1 L). The blade was subequal or longer (Fig. 1 L) than the outer branch in most specimens. Shorter blades (Fig. 1 K) were found in a total of nine specimens from Brazil, Tobago, Florida, and Georgia. In a total of three specimens from Brazil and Tobago, the apical end of the inner stylet was more similar to that in Fig. 1 D, whereas in the remaining specimens like in Fig. 1 K.

Third pleopod in the terminal male (n = 16). Despite its high complexity, the third pleopod at this stage (Fig. 2 D in Heard and Price, 2006) did not show any conspicuous individual or regional variations in the material from Costa Rica, Tobago, Florida, Georgia, and South Carolina. Inner ramus of the blade with numerous protuberances. Outer stylet less than half the length of the blade. Inner stylet reaching to more than 70% the length of the outer stylet, in one male (8.3 mm) from Tobago overreaching the entire outer stylet. Inner stylet with a large, leaf-like, striated ramus.