Carcinonemertes caissarum, 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 : 921-922

Carcinonemertes caissarum new species

( Figure 2A–D )

Diagnosis

Body color varies from translucent white to cream; male with a red spot at posterior end. Two eyes, black. Anterior end of body rounded, posterior end rounded or truncated (males). Worms 1.2–11.0 mm long. Accessory stylets absent. Ovaries arranged in one row on each side of intestine. Takakura’s duct present. Ornamented and filiform mucus sheath may be present in adult worms.

Material examined

Nine females and eleven males were examined. Holotype: female, from the egg mass of Hepatus pudibundus ; type locality: Poço Beach, São Sebastião Island, Brazil, (23 ° 459S, 45 ° 169W), 16 September 2002; Coll. Cynthia Santos; MZUSP No. 003. Paratype: female, from the egg mass of H. pudibundus ; type locality Poço Beach, São Sebastião Island, Brazil, (23 ° 459S, 45 ° 169W), 16 September 2002; Coll. Cynthia Santos; MZUSP No. 004.

Etymology

The species name is a noun in the genitive plural and is in recognition of the human communities known as ‘‘caiçaras’’ (a tupi-guarani word), which are found in the localities where the crabs were collected. The people of these communities depend mainly on fisheries; therefore, this name honors the fishermen who helped us collect, Rogério dos Santos Júnior and his father, Rogério dos Santos.

Description

The description is based on living adults. Measurements are given in mean¡SE (range, number of specimens observed).

Female. Body color varied from translucent white to cream; gut varied from orange to brownish; gonads translucent white. Two eyes, black, round or cup-shaped; round eyes the most common shape. Found free among egg mass of host or in a filiform, ornamented mucus sheath ( Figure 2A ). Lapilli 7¡0 mm (7–8 mm; n 52) in height, larger at center of sheath and smaller and scarce at extremities. Anterior and posterior end of body rounded. Dimensions of relaxed worms 5.5¡1.0 mm (2.6–11.0 mm; n 57) long and 282¡ 20 mm (210–376 mm; n 58) wide. Eye 11¡ 9 mm (8–15 mm; n 59) long and 9¡ 1 mm (5–12 mm; n 59) wide. Distance between eyes 112¡ 11 mm (75–160 mm; n 57). Distance from eyes to tip of head 115¡ 6 mm (100–155 mm; n 59). Brain 97¡ 6 mm (88–120 mm; n 55) long and 46¡ 2 mm (40–52 mm; n 57) wide. Distance from brain to tip of head 132¡ 6 mm (120– 160 mm; n 56). Anterior proboscis chamber could not be distinguished. Diaphragm 38¡ 2 mm (30–48 mm; n 58) long and 46¡ 2 mm (38–55 mm; n 57) wide. Single stylet on basis 8¡ 1 mm (5–10 mm; n 58) long. Stylet basis 22¡ 1 mm (20–25 mm; n 59) long and 7¡0 mm (5–8 mm; n 59) wide. Stylet:basis ratio 0.378 (0.250 –0.500; n 58). Distance from central stylet to tip of head 160¡ 8 mm (122–190 mm; n 58). Accessory stylets absent. Proboscis bulb 26¡ 2 mm (20–38 mm; n 58) long and 30¡ 2 mm (22–38 mm; n 58) wide. Posterior proboscis 70¡ 4 mm (55–88 mm; n 54) long and 59¡ 4 mm (52–68 mm; n 54) wide. Ovaries arranged in one row on each side of the intestinal diverticula. Number of ovaries 158¡30 (76–252; n 55). Distance from first gonad to tip of head 568¡ 56 mm (430–900 mm; n 58).

Male. Body color cream with a red spot at the posterior end; gut varied from orange to brownish; gonads translucent white. Two eyes, black, irregular, circular or cup-shaped. Found free among egg mass of host or in a filiform, ornamented mucus sheath. Lapilli 4 mm (n 51) in height. Anterior end of body rounded, posterior end rounded ( Figure 2B ) or truncated. Dimensions of relaxed worms 2.0¡ 0.3 mm (1.2–4.0 mm; n 59) long and 400¡ 25 mm (230–520 mm; n 511) wide. Eye 11¡ 1 mm (8–15 mm; n 510) long and 10¡0 mm (8–12 mm; n 510) wide. Distance between eyes 107¡ 9 mm (62–150 mm; n 58). Distance from eyes to tip of head 106¡ 7 mm (60–130 mm; n 510). Brain 110¡ 6 mm (86– 125 mm; n 58) long and 54¡ 4 mm (38–75 mm; n 58) wide. Distance from brain to tip of head 135¡ 9 mm (80–170 mm; n 58). Anterior proboscis chamber could not be distinguished. Diaphragm 42¡ 4 mm (30–60 mm; n 57) long and 42¡ 2 mm (32–50 mm; n 57) wide. Single stylet on basis 8¡ 1 mm (5–10 mm; n 59) long. Stylet basis 21¡ 1 mm (18– 25 mm; n 510) long and 7¡0 mm (5–8 mm; n 59) wide ( Figure 2C ). Stylet:basis ratio 0.372 (0.250 –0.571; n 59). Distance from central stylet to tip of head 172¡ 13 mm (110–216 mm; n 58). Accessory stylets absent. Proboscis bulb 22¡ 2 mm (20–25 mm; n 52) long and 30 mm (n 51) wide. Posterior proboscis could not be observed. Distance from first gonad to tip of head 325¡ 46 mm (230–510 mm; n 55). Seminal vesicle easily visible under stereomicroscope in the majority of adult male worms.

Infestation site

Adult worms were found in the host’s egg mass (ovigerous females with eggs in initial, intermediate and final stages of development). Immature worms were found on the ventral side of the abdomen of adult male crabs; on the abdomen, at the gonopores, at the base of pleopods and encysted on the setae of pleopods ( Figure 2D ) of non-ovigerous adult female crabs; encysted on the setae of pleopods of ovigerous females; on the abdomen, at the gonopores, on the arthrodial membrane of pleopods, and encysted on the setae of pleopods of post-ovigerous females.

Figures

Figure 2. Carcinonemertes caissarum n. sp. (A) Filiform mucus sheath of adult worm; (B) male with rounded posterior end; (C) stylet and basis (arrow) in a male worm; (D) juvenile worm encysted on pleopod setae of Hepatus pudibundus.