Conaperta earnhardti, Hooge, Matthew D., Smith, Julian P. S. & Iii, 2004

Hooge, Matthew D., Smith, Julian P. S. & Iii, 2004, New acoels (Acoela, Acoelomorpha) from North Carolina, Zootaxa 442, pp. 1-24 : 9-11

Conaperta earnhardti sp. nov. ( Figs. 6–8)

Type Material: Holotype. AMNH PLATY 1647, set of 1.5­µm­thick serial sagittal sections of epoxy­embedded specimen stained with toluidine blue, collected October 2002. Paratypes. AMNH PLATY 1648, set of 1.5­µm­thick serial sagittal sections; AMNH PLATY 1649, epoxy­embedded whole mount.

Type Locality. Oak Island, NC, from shallow subtidal medium grained sand inside Lockwoods Folly Inlet (33° 54' 53"N, 78° 14' 06"W).

Other Material Examined. Living specimens in squeeze preparations; four sets of 1.5­µm­thick serial sagittal sections of epoxy­embeded specimens; whole mounts for fluorescence imaging of musculature (eight specimens).

Etymology. Species named in memory of race­car driver, and North Carolina native, Dale “The Intimidator” Earnhardt.

Description. Examined specimens 350 to 650 µm long and ~125 µm wide ( Figs.6 A, B, 7A, 8A). Body cylindrical. Anterior and posterior ends rounded.

Epidermis completely ciliated. Body without coloration in transmitted light, but gut contents green in color. Many mucoid glands present; arranged in distinct rows.

Body­wall musculature with circular muscles that encircle the body along entire length of animal; straight longitudinal muscles present between frontal organ and anterior edge of mouth; longitudinal muscles with a longitudinal orientation anteriorly that bend medially to cross diagonally over the body (longitudinal­cross­over fibers present in dorsal and ventral body walls; longitudinal muscles in the anterior half of body that wrap around the posterior rim of mouth (U­shaped muscles) present in ventral body wall ( Fig. 8 A).

Frontal organ well developed; cell bodies of frontal glands positioned ~100 µm behind frontal pore ( Fig. 6 B).

Mouth opening on ventral surface, middle of body. Digestive central syncytium extends from frontal glands posteriorly to level of male copulatory apparatus.

Ovaries paired, ventral; extend from frontal glands posteriorly to bursal nozzle ( Fig. 6 B).

Testes paired, lateral to eggs, compact; separate from ovary. Testes extend from level of statocyst posteriorly to level of bursal nozzle.

Common genital pore opens posteriorly to male copulatory apparatus and anteriorly to vagina ( Figs. 6, 7 B, C).

Vagina positioned somewhat to the right side of male copulatory organ, rather than directly anteriorly. Vagina filled glandular secrections in the form of tear drop­shaped clusters of granules. Vagina surrounded by thick muscular sphincter ( Figs. 6, 7 , 8 B). Walled seminal bursa leads to well­developed bursal nozzle ( Figs. 6, 7 B, C).

Gonopore opens directly to well­developed penis ( Figs. 6 C, 7C). Slightly curved penis with outer longitudinal and inner circular muscle fibers that surround lumen filled with spherical clusters of granular gland secretions ( Figs. 6 A, 7B, C, 8C). Proximal end of penis somewhat bulbous. Penis invaginated into muscular seminal vesicle filled with sperm that surrounds proximal end of penis.

Remarks. The unusual vagina in Conaperta earnhardti distinguishes it from other known species of the genus. The distinctive granular secretions in the lumen of the vagina, and the sizable muscular sphincter surrounding the vagina are diagnostic characters for this species. Conaperta krana and C. thela also have vaginal sphincters (although much less well­developed that that of C. earnhardti ), but these species have differently constructed penes, and have eye­spots and zooxanthellae—features absent in C. earnhardti .

Figures

FIGURE 7. Conaperta earnhardti sp. nov.; photomicrographs. A. Ventral view of living specimen. B. Sagittal view of reproductive organs in living specimen. C. Sagittal histological section. bn, bursal nozzle; e, egg; p, penis; sb, seminal bursa; sph, muscular sphincter surrounding vagina; sv, seminal vesicle.

FIGURE 8. Conaperta earnhardti sp. nov.; whole­mount stained with Alexa­ 488 ­ labeled phalloidin and viewed with confocal microscopy. A. Projection of ventral body­wall musculature. For explanation of muscle patterns see Hooge (2001). B. Projection of musculature associated with reproductive organs. C. Projection showing penis musculature inside of seminal vesicle. cm, circular muscles; cop, male copulatory aparatus; lpm, longitudinal penis muscle; m, mouth; p, penis; sph, muscular sphincter surrounding vagina; u, U­shaped muscles; vcm, ventral crossover muscles.