One specimen up to about 30 mm long and 1 mm wide; dorsoventrally flattened, cephalic lobe broadly rounded anteriorly; caudal terminus blunt. Ochre with numerous small dark dots arranged in longitudinal lines, dark brown rings of differing thickness spaced irregularly along body, first four rings thickest. Prominent but short, vertical cerebral organ furrows demarcate head from rest of body. Eyespots lacking. Mouth ventral, just posterior to cephalic grooves. Proboscis pore subterminal. Lateral sensory organ present in fourth ring. Worm secretes and lives in soft tube of honey color.

Curaçao (Corrêa 1963); Florida and Virgin Islands, USA (Corrêa 1961); São Paulo, Brazil (Corrêa 1954); Santa Marta, Colombia.

Six specimens up to about 50 mm long, 2 mm wide; dorsoventrally flattened; cephalic lobe broadly rounded. Milky ground color; dorsally with abundant short interrupted reddish to brown longitudinal lines, paler or completely absent on ventral surface. Shallow, cerebral organ furrows post-cerebral, vertical and slightly oblique, with inconspicuous, orthogonally oriented secondary furrows. Numerous ocelli arranged irregularly along antero-lateral margin of head. Mouth ventral, posterior to cerebral organ furrows. Proboscis pore at anterior of head; proboscis short and thin.

This species seems to be circumglobal in tropical and subtropical seas (Norenburg 2009).

Fifteen specimens up to about 160 mm long, 2.5 mm wide; dorsoventrally flattened; head elongate, can be pointy; short, slender caudal cirrus present. Black body, lips of cephalic furrows, tip of head and tail grayish or milky white. Deep cephalic furrows form lateral margins of head. Ocelli lacking. Mouth ventral, a large longitudinal slit posterior to cephalic furrows. Proboscis long, yellow, with smooth surface when everted.

Curaçao (Corrêa 1963), Gulf of Mexico (Norenburg 2009); Santa Marta.

This was the most frequently found species, though not necessarily the most abundant; we did not do quantitative sampling in this study. Given the wide regional distributions of other nemerteans in this and other recent studies (e.g., Corrêa 1961, 1963; Norenburg 2009) one expects such a common species to be identifiable as a regionally known species. Many of the early descriptions, however, are based on highly contracted and, often, fragmented specimens and lack observations from life (e.g., Verrill 1900; Coe 1901; Stiasny-Wijnhoff 1920). Presence or absence of a caudal cirrus is unreliably known for several named species from the region that are more or less blackish. The genera Cerebratulus and Micrura, both considered to have a caudal cirrus as a matter of diagnosis, are known among nemertean specialists to be fraught with taxonomic inconsistencies (see, e.g., Schwartz and Norenburg 2001, 2005). The presence or absence of a caudal cirrus seems, based on DNA data, to be an unreliable diagnostic for those genera (Schwartz 2009). Possible Caribbean options for our species include Cerebratulus leucopsis (Coe 1901), reported to have a caudal cirrus, and Corsoua kristenseni Corrêa, 1963, reported to lack a caudal cirrus. We believe that the former may be synonymous with Dushia atra sensu Corrêa (1963) from Curaçao. Corsoua kristenseni has a small mouth and occurs in mangrove habitat, whereas Dushia atra sensu Corrêa (1963) has a large mouth and occurs at the high-water line in clean sand under rubble, as do our specimens, though Corrêa (1963) does not mention a caudal cirrus. Our material consistently has a small caudal cirrus but it could easily be missed in preserved specimens. Pending anatomical studies, we assign our specimens to Dushia atra sensu Corrêa (1963). A potential taxonomic problem remains in that Girard (1893) describes his specimens as having been dredged from deep water off Cape Florida, which is at strong variance with the very narrowly constrained habitat of our specimens and those found on other Caribbean islands (JLN, pers obs).

One specimen up to about 30 mm long, 2 mm wide; dorsoventrally flattened, anterior margin somewhat squared, posterior end tapered, caudal cirrus absent. Body dark violet or dark olive green; paired, widely spaced, transversely elongate white markings dorsally, each pair part of barely perceptible thin white ring encircling body; anterior two-thirds of head white with prominent brown pigment patterning, including a V-shaped marking dorsally and ventrally, each pointed anteriorly. Deep cephalic furrows form lateral margins of head. About 20 to 30 small ocelli disposed in a single irregular line on each side of head along anterior third of cephalic furrow. Mouth ventral, a large longitudinal slit posterior to cephalic furrows. Cephalic ganglion visible through body wall as a pink mass.

Florida (Coe 1951), Belize (JLN, pers obs); Santa Marta, Colombia.

Coe (1951) named Lineus stigmatus from the shore of Biscayne Bay, Florida. He illustrates and describes in useful detail only the posterior portion, and this agrees strongly with the pattern of paired white markings seen in our specimen, which is not known from any other nemerteans in the region. We believe that it is reasonable to assign our specimens to Coe’s species; we base this on the distinctive color pattern and the strong regional distribution overlaps for many of the other regional nemertean species. Though Coe (1951) noted a potential similarity with Lineus albocinctus Verrill, 1900, we judge the color patterns to be very different. Coe (1951) also comments “…color pattern in this species has a superficial resemblance to that of some individuals of Lineus geniculatus (D. Chiaje) in which the white rings are interrupted in the mid dorsal line but in the latter species the rings continue laterally and ventrally”. Riser (1991) resurrected Notospermus (Huschke, 1830) and transferred to it Lineus geniculatus (sensu Delle Chiaje, 1828) of several authors. We agree that the pigment pattern resembles that of Notospermus geniculatus as well as that of a variety of similar worm images available via the internet and attributed to Notospermus geniculatus (JLN, pers obs). We anticipate that Lineus stigmatus is congeneric with Notospermus geniculatus, but this needs to be corroborated with internal anatomy and/or molecular data.

Two specimens up to about 100 mm long, 3 mm wide; dorsoventrally flattened; head “triangular”, pointed anteriorly and widening posteriorly; posterior end blunt with short and slender caudal cirrus. Orange grading posteriorly to yellowish. Deep cephalic furrows form lateral margins of head. Mouth slit-shaped, posterior to cephalic grooves. Eyespots lacking. Proboscis long, thick and pink; when everted it possesses ruffles.

Belize (Schwartz and Norenburg 2005); Caribbean coast of Panama (Collin et al. 2005); Santa Marta, Colombia.

Two specimens up to about 20 mm long, < 1 mm wide; dorsoventrally flattened, bluntly rounded at both ends. Pale yellow, with three thin, longitudinal blood vessels made bright red by corpuscles that can be observed flowing through the vessels. Cerebral organ furrows, vertical, not prominent, precerebral. About 6–10 conspicuous, blackish, precerebral ocelli, in single row along each. Rhynchopore subterminal at tip of head; rhynchocoel extends to about middle of body length; proboscis long and thick; armature approximately at center of proboscis; stylet slender (length: 30 µm), supported on cylindrical basis (33 × 8 µm); 2 pouches with 3 accessory stylets each. Mature females with dark or bright gray eggs visible through body wall.

Gulf of Mexico, New England (USA) and Washington (Norenburg 2009); California (Coe 1940); Santa Marta, Colombia.

Four specimens up to about 10 mm long, 0.5 mm wide; dorsoventrally flattened, bluntly rounded at both ends. Variable color, yellowish to milky gray, sometimes with light orange pigmentation in cephalic region corresponding to cerebral ganglia. Cerebral organ furrows vertical, precerebral. About 6-10 conspicuous, blackish, precerebral ocelli, arranged in single regular row, along each lateral margin of head. Rhynchopore subterminal; rhynchocoel about three quarters of body length; proboscis long; medially constricted basis same length as slender stylet (length: 29 µm); 2 pouches with 2 accessory stylets each.

Gulf of Mexico and New England (USA) (Norenburg 2009); Santa Marta, Colombia.

Four specimens up to about 15 mm long, 0.5 mm wide; dorsoventrally flattened, bluntly rounded at both ends; cephalic lobe narrower than foregut region. Dark brown body; with magnification, thick unpigmented margin (i.e., epidermis) appears white. Cerebral organ furrows vertical, precerebral. Row of about 6 ocelli present along each lateral margin of head; visible in squeeze preparation. Rhynchopore subterminal; proboscis large and thick, conspicuous papillae; central stylet slender (length: 42 µm), supported on wide cylindrical basis (34 × 10 µm) at middle of proboscis; two pouches with 2-4 accessory stylets each.

Gulf of Mexico and Southern Florida (Norenburg 2009); Curaçao (Schwartz and Norenburg 2005); Santa Marta, Colombia.

One specimen up to about 20 mm long; 1 mm wide; rounded at both ends. Yellow milky base color, dorsally with 2 brown to reddish longitudinal lines joined at anterior and posterior ends. Cerebral organ furrows precerebral, difficult to see. Head almost undifferentiated from body. Cephalic grooves not visible. Two pre-cerebral eyes on each lateral margin of head. Rhynchopore subterminal; proboscis small, slender provided with papillae; short central stylet (length: 11 µm), supported on a massive base (27 × 7 µm). Two pouches containing three accessory stylet each.

USA East Coast – Florida (Thollesson and Norenburg 2003), South Carolina (Caplins et al. 2012); Atlantic Galician Island (Junoy and Herrera-Bachiller 2010); European waters, Portuguese and Spanish Exclusive Economic Zone, Red Sea (Gibson 2014b); Santa Marta, Colombia.

Caplins et al. (2012) found support suggesting that the two color morphs of Nemertopsis bivittata commonly found sympatrically – one with dorsal stripes that meet anteriorly and the other with lines that do not meet – are genetically isolated. Support includes statistical difference in size of stylets and in DNA sequence differences for mitochondrial cytochrome-oxidase-1 gene – minimum and an a maximum pair-wise difference of 13.6% and 19.9% – (Caplins et al. 2012). Though awaiting explicit molecular data, Norenburg (2013) commented that Nemertopsis bivittata and Nemertopsis gracilis Coe, 1904, probably are synonyms and, therefore, following Sun and Dong (1998), the morph with lines meeting would be Nemertopsis bullocki Coe, 1940 and the one with stripes not meeting would be, by priority, Nemertopsis bivittata (Delle Chiaje, 1841). For now, we do not formally distinguish the two here and assign our specimen at Nemertopsis bivittata.

Up to about 12 mm long; < 1 mm wide; according to (Corrêa 1954), small meiofaunal worm dorsoventrally flattened, tapered at posterior end. Cream color. Cerebral organs and furrows present, precerebral. Eyes absent. Long sensory cirri along anterior and lateral margins of head. Pair statocysts; statolith an aggregation of 3 spherical granules. Rhynchocoel approximately half of body length; proboscis long, stout, with long papillae; anterior papillae (closest to proboscis insertion) each with rod-shaped inclusion; posterior proboscis opaque in transmitted light (white with incident light); stylet slender, > 2× length of pyriform basis; 2 pouches with 6 accessory stylets each.

Brazil (Corrêa 1950); Guajira, Colombia (Kirsteuer 1977).

Two specimens up to about 3.5 mm long; < 0.3 mm wide; truncated at both ends. Milky white color. Cerebral organs and associated furrows absent. Without ocelli. Two ovoid statocysts present, statolith formed by more than 10 spherical granules. Rhynchocoel short, about one-third of body length; proboscis very short; posterior proboscis vesicular (translucent) with transmitted light; armature at middle of proboscis; stylet slender, helically sculpted (length: 15 µm); basis thin, cylindrical (14 × 2 µm); 2 pouches with 3 accessory stylets each.

Brazil (Corrêa 1950); Guajira, Colombia (Kirsteuer 1977); Santa Marta, Colombia.

One specimen up to about 12 mm long, 1 mm wide; dorsoventrally flattened, bluntly rounded at both ends. Body vivid pinkish strawberry-red. Cerebral organ furrows shallow, precerebral. Pair irregular rows of 8-13 ocelli each on each side of head; row of about 10 ocelli between brain and each lateral margin of body and reaching post-cerebrally into foregut region. Rhynchopore subterminal; rhynchocoel to about middle of body length; proboscis long and thick with thin papillae; central stylet thin (length: 45 µm); basis smooth, cylindrical (54 × 14 µm); 2 pouches with 2 or 3 accessory stylets each. Epidermis with minute crescent-shaped intracellular spicules.

São Sebastião (Brazil) (Corrêa 1954); Santa Marta, Colombia.

Six specimens up to about 30 mm long, < 2 mm wide; dorsoventrally flattened, bluntly rounded at both ends. Variable color, from white to yellow or greenish. Cerebral organ furrows shallow, precerebral. Numerous pre-cerebral small ocelli arranged in two pair irregular rows of about 15–20 ocelli each; row of post-cerebral ocelli each side between brain and lateral margin of body, extending far posterior to brain along lateral nerve cord. Rhynchopore subterminal; rhynchocoel wide and almost full body length; proboscis long with small papillae; stylet slender (length: 60 µm) supported on massive and medially constricted basis (112 × 28 µm); two pouches, each bearing 3 accessory stylets. Epidermis with minute crescent-sphaped intracellular spicules.

Gulf of Mexico and New England (Norenburg 2009); California and Oregon (Corrêa 1964); Southern Florida and Virgin Islands (Corrêa 1961); Gulf of Maine (Gibson 2014c); North Atlantic (Azores) (Strand 2002); Santa Marta, Colombia.

One specimen about 17 mm long, < 1 mm wide; dorsoventrally flattened, tapered at both ends. Gray to brown color, darker on head and along mid-dorsal line of body; ventral surface milky gray. Head narrow with respect to body. Cerebral organ furrows wide, postcerebral, subdivided by about 5 longitudinal epithelial ridges (secondary furrows) orthoganol to furrow axis. Numerous large ocelli, precerebral, arranged in four irregular longitudinal rows, outer rows possibly divided into anterior and posterior clusters. Armature normally several stylets supported on a single basis, but not documented by us. Individuals capable of swimming by undulatory movements, leaving mucus behind it.

Bahía Mochima (Venezuela) (Kirsteuer 1973); Santa Marta, Colombia.

Two named polystiliferan species are known from the region. Polyschista curacaoensis Stiasny-Wijnhoff, 1925 is known only from three pieces – two heads and a tail – already preserved and strongly contracted when first examined by Stiasny-Wijnhoff; therefore, of dubious value for anatomical study. The heads are described as having a “a well defined brown longitudinal marking on their back” while “the margins are a milky, transparent white and two to three times as broad as the thick [brown] middle part”. The tail is described as being transparent and white. This does not fit well the present species. Curranemertes natans Kirsteuer, 1973 is known only from Venezuela and described as “orange to brownish” dorsally, with the thicker median region of the head being a “darker brownish shade”. Though Kirsteuer (1973) concludes that the two species differ in internal anatomy, he cites only character states that he presumes “probably” differ in Polyschista. We are not sanguine that our specimen is either species, though it resembles specimens previously collected by JLN off Belize and Bocas del Toro, Panama and identified as Curranemertes cf. natans.

Härlin (1998), with support from a morphological phylogenetic analysis re-assigned Curranemertes natans to the phylo-clade Punnettia. Härlin and Härlin (2000) found Punnettia to be paraphyletic but without placing the type species, Punnettia hubrechti. They concluded by discarding Punnettia, in a Phylocode act, with the argument that it is “a messy name” and assigning its species to two phylo-clades but without placing Punnettia hubrechti. Thus, with respect to a Linnean classification, we cannot know which Punnettia species would remain so, because they form a clade with Punnettia hubrechti. Hence, it seems more appropriate at this time to retain Curranemertes natans, pending resolution of Punnettia phylogeny.