Carcinonemertes divae, Santos & Norenburg & Bueno, 2006

Santos, Cynthia, Norenburg, Jon L. & Bueno, Sérgio L. S., 2006, Three new species of Carcinonemertes (Nemertea, Carcinonemertidae) from the southeastern coast of Brazil, Journal of Natural History 40 (15 - 16), pp. 915-930 : 917-920

Carcinonemertes divae new species

( Figure 1A–F )

Diagnosis

Body color varies from translucent white to orange. Two eyes, black. Anterior end of body rounded or pointed; posterior end pointed. Worms 1.3–4.3 mm long. Accessory stylets absent. Ovaries arranged in one row on each side of intestine. Takakura’s duct present. Ornamented and filiform mucus sheath attached to pleopods of hosts may be present in adult worms.

Material examined

Fourteen females, 16 males and one larva were examined. Holotype: male, from the egg mass of Libinia spinosa ; type locality: Poço Beach , São Sebastião Island, Brazil, (23 ° 459S, 45 ° 169W), 18 Jul 2003; Coll. Cynthia Santos; MZUSP No. 001. Paratype: female, from the egg mass of L. spinosa ; type locality: Poço Beach, São Sebastião Island, Brazil (23 ° 459S, 45 ° 169W); 18 Jul 2003; Coll. Cynthia Santos; MZUSP No. 002 .

Etymology

The species name is a noun in the genitive singular and honors Dr Diva D. Corrêa, a Brazilian nemertean specialist, formerly from the Universidade de São Paulo, who dedicated almost 40 years of her life to the study of nemerteans and greatly contributed to the knowledge of this phylum.

Description

The description is based on living adults and one larva. The latter was obtained from crabs collected at Anchovas Beach. Measurements are given as mean¡SE (range, number of specimens observed).

Female. Body color varied from translucent white to orange; gut orange; gonads translucent white. Two eyes, black, irregular, circular or elliptical; elliptical eyes the most common shape. Found free among egg mass of host or in a filiform, ornamented mucus sheath attached to the pleopods. Lapilli homogeneously distributed on mucus sheath and 4¡ 1 mm (3–5 mm; n 52) in height. Anterior end of body rounded or pointed ( Figure 1A ); posterior end pointed. Dimensions of relaxed worms 2.6¡ 0.1 mm (1.3– 3.2 mm; n 514) long and 332¡ 17 mm (200–480 mm; n 514) wide. Eye 26¡ 1 mm (20– 36 mm; n 513) long and 16¡ 1 mm (10–20 mm; n 513) wide. Distance between eyes 103¡ 4 mm (80–130 mm; n 512). Distance from eyes to tip of head 143¡ 9.5 mm (100– 204 mm; n 512). Brain 117¡ 9 mm (92–150 mm; n 57) long and 57¡ 3 mm (45–70 mm; n 57) wide. Distance from brain to tip of head 171¡ 7 mm (140–200 mm; n 58). Proboscis aligned in a straight line ( Figure 1B ). Anterior proboscis chamber 75 mm (n 51) long and 12 mm (n 51) wide. Diaphragm 53¡ 2 mm (42–80 mm; n 514) long and 54¡ 3 mm (45–78 mm; n 514) wide. Single stylet on basis, 10¡ 1 mm (8–12 mm; n 513) long. Stylet basis 25¡ 1 mm (22–30 mm; n514) long and 7¡0 mm (5–8 mm; n 514) wide ( Figure 1C ). Stylet:basis ratio 0.387 (0.250 –0.500; n 513). Distance from central stylet to tip of head 221¡ 20 mm (130– 400 mm; n 512). Accessory stylets absent. Proboscis bulb 36¡ 2 mm (22–48 mm; n 512) long and 45¡ 2 mm (38–56 mm; n 514) wide. Posterior proboscis 57¡ 6 mm (30–72 mm; n 56) long and 51¡ 5 mm (35–68 mm; n 57) wide. Ovaries arranged in one row on each side of the intestinal diverticula. Number of ovaries 31¡4 (13–53; n 511). Distance from first gonad to tip of head 428¡ 17 mm (348–540 mm; n 512).

Male. Body color cream; gut orange; gonads translucent white. Two eyes, black, irregular, circular or elliptical; elliptical eyes the most common shape. Found free among egg mass of host or in a filiform, ornamented mucus sheath attached to the pleopods. Lapilli homogeneously distributed on mucus sheath and 4 mm (n 51) in height. Anterior end of body rounded or pointed ( Figure 1D ), posterior end pointed ( Figure 1E ). Dimensions of relaxed worms 2.6¡ 0.2 mm (1.3–4.3 mm; n 514) long and 316¡ 32 mm (170–720 mm; n 516) wide. Eye 29¡ 2 mm (22–48 mm; n 516) long and 17¡ 1 mm (10– 25 mm; n 516) wide. Distance between eyes 96¡ 3 mm (75–112 mm; n 515). Distance from eyes to tip of head 160¡ 10 mm (110–230 mm; n 516). Brain 118¡ 9 mm (90–175 mm; n 59) long and 52¡ 3 mm (45–70 mm; n 57) wide. Distance from brain to tip of head 212¡ 5 mm (200–260 mm; n 513). Proboscis aligned in a straight line. Anterior proboscis chamber 46¡ 6 mm (40–52 mm; n 52) long and 18 mm (n 52) wide. Diaphragm 48¡ 1 mm (45–55 mm; n 514) long and 50¡ 2 mm (38–60 mm; n 514) wide. Single stylet on basis 10¡0 mm (8–12 mm; n 513) long. Stylet basis 28¡ 1 mm (22–30 mm; n 515) long and 7¡0 mm (5–10 mm; n 515) wide. Stylet:basis ratio 0.371 (0.250 –0.500; n 513). Distance from central stylet to tip of head 231¡ 14 mm (160–310 mm; n 513). Accessory stylets absent. Proboscis bulb 35¡ 2 mm (25–48 mm; n 513) long and 39¡ 2 mm (25–48 mm; n 513) wide. Posterior proboscis 72¡ 11 mm (40–100 mm; n 55) long and 48¡ 1 mm (25– 50 mm; n 56) wide. Distance from first gonad to tip of head 475¡ 9 mm (370–500 mm; n 512). Seminal vesicle ( Figure 1E ) easily visible under stereomicroscope in the majority of adult male worms.

Larva. Body ciliated with anterior and posterior ciliary tuft. Body shape spherical or ovoid. Two eyes. Length 110 mm (n 51). Width 70 mm (n 51). Anterior tuft 20 mm (n 51) in length. Posterior tuft 24 mm (n 51) in length. Eye 12 mm (n 51) long and 6 mm (n 51) wide. Distance between eyes 22 mm (n 51). Distance from eyes to tip of head 33 mm (n 51).

Infestation site

Adult worms were found in the host’s egg mass ( Figure 1F ) (ovigerous females with eggs in initial, intermediate and final stages of development). Immature worms were found on the abdomen of juvenile male crabs; on the abdomen and at the arthrodial membrane of pereopods of juvenile female crabs; at the base of pereopods, on the ventral and dorsal sides of the abdomen of adult male crabs; on the ventral and dorsal sides of the abdomen of nonovigerous adult female crabs; at the base of pleopods, on the abdomen and on the eggs of ovigerous females; at the base of pleopods and on the ventral side of the abdomen of postovigerous females.

Figures

Figure 1. Carcinonemertes divae n. sp. (A) Anterior end of female, (B) proboscis aligned in a straight line, (C) stylet and basis (arrow) in a female worm, (D) male with rounded anterior end, (E) pointed posterior end of male, with seminal vesicle, (F) adult female (arrow) on Libinia spinosa eggs. Abbreviations: b, proboscis bulb; d, diaphragm; p, posterior proboscis chamber.