Prosadenoporus Bürger, 1890

Maslakova, Svetlana A. & Norenburg, Jon L., 2008, Revision of the smiling worms, genera Prosadenoporus Bürger, 1890 and Pantinonemertes Moore and Gibson, 1981 and description of a new species Prosadenoporus floridensis sp. nov. (Prosorhochmidae; Hoplonemertea; Nemertea) from Florida and Belize, Journal of Natural History 42 (25 - 26), pp. 1689-1727 : 1693-1697

Prosadenoporus Bürger, 1890

Prosadenoporus Bürger, 1890 .

Neonemertes Girard, 1893 . New synonymy. Type species Tetrastemma agricola Willemoes-Suhm, 1874 by monotypy.

Pantinonemertes Moore and Gibson, 1981 (part). New synonymy. Type species Pantinonemertes winsori Moore and Gibson, 1981 by original designation.

Type species

Prosadenoporus arenarius Bürger, 1890 , by subsequent designation ( Moore and Gibson 1988).

Etymology

‘‘Pro’’5before, forward, in front of, L.; ‘‘adeno, adenos’’5gland, G.; ‘‘poros’’5hole, G. Likely refers to the presence of well-developed frontal organ [anterior pore] through which mucus cephalic glands discharge.

Diagnosis

Monostiliferous marine, brackish-water, semi-terrestrial or terrestrial hoplonemerteans with a horizontal cephalic epithelial fold (prosorhochmid smile) ( Figures 1D, 1E and 2B ). Four eyes ( Figures 1A, 1D, 1E and 2B ). Body-wall musculature well developed with a delicate layer of diagonal muscles between outer circular and inner longitudinal muscle layers ( Figures 3A and 3B ). Rhynchocoel full body-length, with wall composed of distinct outer circular and inner longitudinal muscle layers ( Figure 3K ). Proboscis small or massive, may be used for rapid locomotion. If massive, proboscis often with increased number of proboscis nerves and accessory stylet pouches, longer stylet (S) and basis (B) and decreased S:B ratio ( Table 3). Tubular frontal organ is long and exceptionally well developed, with laterally differentiated epithelium ( Figures 3C , 4 I–L, 5G–I, 7A–I, 7L, 8A–D and 9C–F). Cephalic glands extensive, reaching into stomach-pylorus region and containing basophilic (mucus) components ( Figure 3C ) discharging through frontal organ and via improvised epidermal ducts and acidophilic (proteinaceous) components, staining red (red glands) ( Figure 5H) and orange with Mallory trichrome and its modifications (orange-G glands) ( Figures 5J, 6B and 6D ). Proteinaceous cephalic glands discharge via improvised ducts scattered throughout epidermis. Cerebral sensory organs small, anterior or antero-lateral to brain, with simple un-forked canal, opening ventro-laterally into reduced cerebral organ furrows ( Figures 2A , 5A, 5B and 5J). Neurochord cells and neurochords present in some species ( Figures 5E, 5F, 7J , 8E, 8F and 9G ), but not necessarily together. Lateral nerve cords without accessory nerves (e.g. Figures 4G and 7J ). Oesophagus divisible into anterior region supplied with acidophilic glands ( Figures 3F, 3I, 3J , 5J, 6A and 6B ), and posterior non-glandular region ( Figures 3G and 6C ). Caecum long, anteriorly bifid, with numerous lateral diverticula on each side ( Figure 6E ). Blood system with three main longitudinal vessels, without transverse connectives; mid-dorsal blood vessel with single vascular plug ( Figure 4F ); cephalic vascular loop recurved. Extracellular matrix (parenchyma) may be very extensive, especially in large species. Excretory system well developed, with binucleate terminal nephridial cells reinforced by transverse support bars ( Figures 5C, 5D and 7K ), thin-walled canals and large number of inconspicuous nephridiopores. Gonochoric or hermaphroditic. Oviparous or viviparous.

Composition

Prosadenoporus includes nine species: P. agricola ( Willemoes-Suhm, 1874) comb. nov., P. arenarius Bürger, 1890 , P. spectaculum ( Yamaoka, 1940) comb. nov., P. winsori ( Moore and Gibson, 1981) comb. nov., P. enalios ( Moore and Gibson, 1981) comb. nov., P. mooreae ( Gibson, 1982b) comb. nov., P. mortoni ( Gibson, 1990) comb. nov., P. fujianensis ( Sun, 2001) comb. nov., and P. floridensis sp. nov.

Geographic distribution

Atlantic coast of the USA (FL) and Bermuda; Caribbean ( Belize); Pacific coast of USA (Puget Sound, WA to CA); Hong Kong, China (Fujian Province), north-eastern coast of Australia (Queensland), Indonesian Islands (Noordwachter

Island off Sulawesi and Ambon Island [Amboina]), Palau Bidan (Kedah Province) off Malay Peninsula, Laccadive Islands.

Figures

Figure 1. External appearance of members of Prosadenoporus. (A) Female and male of Prosadenoporus floridensis sp. nov.; (B) Prosadenoporus winsori comb. nov. on a piece of rotten mangrove penetrated by teredinid burrows (its natural habitat); (C–D) Prosadenoporus mooreae comb. nov.; (E–F) anterior end of P. winsori (E5lateral view; F5dorsal view). Notes: cg, cerebral ganglia; pf, posterior cephalic furrow; sm, prosorhochmid smile. Scales: (A and C), 3 mm; (B), 20 mm; (D), 0.5 mm; (E and F), 1 mm.

Figure 2. (A–B) Diagrams of anterior end of Prosadenoporus floridensis sp. nov. (A5ventral view; B5dorsal view); (C–D) Pantinonemertes californiensis (C5ventral view; D5dorsal view). Notes: cof, cerebral organ furrow; pf, posterior cephalic furrow; rhst, rhynchostome; sm, prosorhochmid smile.

Figure 3. Histological sections of Prosadenoporus floridensis sp. nov. (dorsal5up; ventral5 down unless otherwise noted). (A) Transverse section through the body wall; (B) longitudinal (tangential) section through the body wall showing diagonal muscle fibres; (C) longitudinal saggital section through the head (anterior to the left) showing frontal organ, cerebral ganglia and voluminous basophilic cephalic glands; (D) transverse section showing well-developed dorso-ventral musculature in the midgut region (arrowhead); (E) transverse section through precerebral region showing rhynchodeum, oesophagus and an ocellus; (F) transverse section through the anterior oesophagus showing acidophilic oesophageal glands and ‘‘splanchnic’’ musculature (arrowheads); (G) transverse section through the posterior oesophagus showing ciliated oesophageal epithelium lacking acidophilic glands; (H) transverse section through the stomach showing ‘‘splanchnic’’ musculature (arrowheads); (I) transverse section through the anterior rhynchodeum; (J) transverse section through the rhynchodeum at the level of the proboscis insertion (ventral to the right); (K) transverse section through the rhynchocoel wall (L) transverse section through anterior-most portion of proboscis (near proboscis insertion) showing distinct proboscis nerves (arrowheads). Notes: bgl, basophilic cephalic glands; cg, cerebral ganglia; cm, circular muscles; ep, epidermis; oes, oesophagus; fo, frontal organ; int, intestine; lm, longitudinal muscles; lnc, lateral nerve cord; ov, ovary; pb, proboscis; pc, ocellus; ps, proboscis insertion muscles; rhc, rhynchocoel; rhd, rhynchodeum; stm, stomach. Scales: (A, B), (F–L), 50 mm; (D–E), 100 mm; (C), 200 mm.

Figure 4. Histological sections of Prosadenoporus floridensis sp. nov. Transverse sections through (A) the proboscis insertion, and (B) anterior proboscis showing proboscis nerves (arrowheads); (C) transverse section through the proboscis showing inner circular muscles; (D–E) transverse sections through the cephalic blood vessels, demonstrating ‘‘valves’’ and ‘‘pouches’’ (arrowheads); (F) transverse section through the vascular plug (arrowhead); (G) transverse section through the lateral nerve cord showing nerve cord muscles (arrowhead); (H) transverse section through the midgut region of a mature female showing large oocytes in the ovary; (I) longitudinal (sagittal) section through the frontal organ (arrowhead) and precerebral region (anterior to the left); (J–L) a series of transverse sections through the anterior (J), middle (K) and posterior (L) portions of the frontal organ showing lateral acidophilic regions (arrowheads). Notes: bgl, basophilic cephalic glands; cg, cerebral ganglia; cm, circular muscles; fo, frontal organ; icm, inner circular musculature; int, intestine; lm, longitudinal musculature; lnc, lateral nerve cord; lum, blood vessel lumen; oct, oocytes; pb, proboscis; pep, proboscis epithelium; rhc, rhynchocoel; rhd, rhynchodeum. Scales: (D–F), 25mm; (A, B, C, G and J–L), 50 mm; (H–I), 200 mm.

Figure 6. (A–E) A series of slightly oblique transverse sections of Prosadenoporus floridensis sp. nov. from precerebral region to pyloric region (proboscis is missing in this individual): (A) Section through the posterior eyes immediately in front of cerebral ganglia; (B) cerebral ganglia, ventral cerebral commissure and anterior oesophagus; (C) cerebral ganglia and posterior oesophagus; (D) stomach; (E) pylorus and caecum. (F) transverse section through the midgut region of another specimen showing ripe testes. Notes: bgl, basophilic cephalic glands; cae, caecum; cbl, cephalic vascular loop; cdiv, caecal diverticulum; cg, cerebral ganglia; cog, cerebral organ gland; dc, dorsal cerebral commissure; oes, oesophagus; int, intestine; lbv, lateral blood vessel; lnc, lateral nerve cord; ogl, orange-G cephalic glands; pb, proboscis; pc, ocellus; pyl, pylorus; rhc, rhynchocoel; rhd, rhynchodeum; stm, stomach; ts, testis; vc, ventral brain commissure. Scales: (A–F), 100 mm.

Figure 7. Microscopic anatomy of Prosadenoporus species.(A–C) A series of transverse sections through the frontal organ of Prosadenoporus enalios comb. nov.; relative position of the lateral acidophilic regions (arrowheads) indicate a noticeable twist of the frontal organ canal; (D) a longitudinal sagittal section through frontal organ of Prosadenoporus mooreae comb. nov. (anterior to the right); (E–I) a series of slightly oblique transverse sections through the frontal organ of P. mooreae comb. nov.; lateral acidophilic regions of the frontal organ (arrowheads), note the twisting of the frontal organ canal; (J) transverse section through lateral nerve cord of Prosadenoporus winsori comb. nov. showing the tentative neurochord (arrowhead); (K) binucleate terminal cells of nephridia (flame cells) of P. winsori comb. nov. (arrowheads); (L) a longitudinal sagittal section through the frontal organ of P. winsori comb. nov. (anterior to the left). Notes: bgl, basophilic cephalic glands; cg, cerebral ganglia; fo, frontal organ; lnc, lateral nerve cord; rhd, rhynchodeum. Scales: (A–C), and (E–I), 50 mm; (D), 100 mm; (J), 30mm; (K), 20mm; (L), 200mm.

Figure 8. (A–D) A series of transverse sections through the frontal organ of Prosadenoporus winsori comb. nov.; relative position of the lateral acidophilic regions (arrowheads) indicate a noticeable twist of the frontal organ canal; (E) Neurochord cell of P. winsori comb. nov. (circled, insert); (F) Neurochord cell of Prosadenoporus fujianensis comb. nov. (circled, insert). Notes: bgl, basophilic cephalic glands; cg, cerebral ganglia; fo, frontal organ; pb, proboscis. Scales: (A–F), 100 mm; inserts, 50 mm.

Figure 9. (A–B) Transverse sections through the frontal organ of Pantinonemertes californiensis; (C–I) Prosadenoporus spectaculum comb. nov.: (C–F) a series of transverse sections through the tip of the head showing frontal organ twisting; lateral acidophilic regions of the frontal organ marked with arrowheads; (G) transverse section through the cerebral ganglia showing two neurochord cells (circled, insert); (H) transverse section through the proboscis insertion and anterior portion of cerebral ganglia showing contracted proboscis insertion muscles; (I) transverse section through the posterior region of brain showing beginning of the lateral nerve cords (asterisks) which appear sectioned longitudinally, presumably because of the severe contraction of the specimen during fixation. Notes: bgl, basophilic cephalic glands; cg, cerebral ganglia; fo, frontal organ; ogl, orange-G cephalic glands; vc, ventral brain commissure. Scales: (A–F), 50 mm; (G), 100 mm (insert, 50mm); (H–I), 200 mm.