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Redescriptions of Nereis oligohalina (Rioja, 1946) and N. garwoodi González-Escalante & Salazar-Vallejo, 2003 and description of N. confusa sp. n. (Annelida, Nereididae).

Conde-Vela VM, Salazar-Vallejo SI - Zookeys (2015)

Bottom Line: Nereis oligohalina (Rioja, 1946) was described from the Gulf of Mexico, but it has been considered a junior synonym of Nereis occidentalis Hartman, 1945, or regarded as a distinct species with an amphiamerican distribution.In order to clarify these uncertainties, Nereis oligohalina is redescribed based on specimens from the Mexican Gulf of Mexico, including a proposed neotype; further, Nereis garwoodi is redescribed including the selection of lectotype and paralectotypes, and Nereis confusa sp. n. is described with material from the Gulf of California.A key for the identification of similar species and some comments about speciation in nereidid polychaetes are also included.

View Article: PubMed Central - PubMed

Affiliation: El Colegio de la Frontera Sur, CONACYT, Departamento de Sistemática y Ecología Acuática, Chetumal, México.

ABSTRACT
Type material of several polychaete species described by Enrique Rioja from Mexican coasts are lost, and the current status of some species is doubtful. Nereis oligohalina (Rioja, 1946) was described from the Gulf of Mexico, but it has been considered a junior synonym of Nereis occidentalis Hartman, 1945, or regarded as a distinct species with an amphiamerican distribution. On the other hand, Nereis garwoodi González-Escalante & Salazar-Vallejo, 2003, described from Chetumal Bay, Caribbean coasts, could be confused with Nereis oligohalina. In order to clarify these uncertainties, Nereis oligohalina is redescribed based on specimens from the Mexican Gulf of Mexico, including a proposed neotype; further, Nereis garwoodi is redescribed including the selection of lectotype and paralectotypes, and Nereis confusa sp. n. is described with material from the Gulf of California. A key for the identification of similar species and some comments about speciation in nereidid polychaetes are also included.

No MeSH data available.


Related in: MedlinePlus

Variation of Nereis species studied. NereisoligohalinaA, D, J–L, O, Q from ECOSUR–OH–P0760. NereisgarwoodiB, E from paralectotype ECOSUR 0066; I, M, R from ECOSUR P2834. Nereisconfusa sp. n. C, F–H, N, P from ECOSUR P2838. A–C Pharynges everted, dorsal view D–F Pharynges everted, ventral view G Pharynx everted, anterior view, showing merged paragnaths (arrows) H Close-up of merged paragnaths on area IV I–J Variations on area I K Variations on areas V and VI L Fingerprint-like pattern, dorsal view M–N Pigmentation patterns on anterior ends, dorsal view O Parapodial furrow in posterior end, lateral view (arrow indicates start) P Specimen on tube, dorsal view Q Parapodium from posterior chaetiger, anterior view R Ventral cirrus duplicated, chaetiger 5, anterior view. Scale bars: 0.5 mm (A–F, L); 1 mm (M–P); 0.1 mm (Q–R).
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Figure 6: Variation of Nereis species studied. NereisoligohalinaA, D, J–L, O, Q from ECOSUR–OH–P0760. NereisgarwoodiB, E from paralectotype ECOSUR 0066; I, M, R from ECOSUR P2834. Nereisconfusa sp. n. C, F–H, N, P from ECOSUR P2838. A–C Pharynges everted, dorsal view D–F Pharynges everted, ventral view G Pharynx everted, anterior view, showing merged paragnaths (arrows) H Close-up of merged paragnaths on area IV I–J Variations on area I K Variations on areas V and VI L Fingerprint-like pattern, dorsal view M–N Pigmentation patterns on anterior ends, dorsal view O Parapodial furrow in posterior end, lateral view (arrow indicates start) P Specimen on tube, dorsal view Q Parapodium from posterior chaetiger, anterior view R Ventral cirrus duplicated, chaetiger 5, anterior view. Scale bars: 0.5 mm (A–F, L); 1 mm (M–P); 0.1 mm (Q–R).

Mentions: Although the species described here have more attributes than those included in the current diagnosis of the genus (Bakken and Wilson 2005), the generic diagnosis was not modified because it first requires a redescription of the type-species, and a phylogenetic analysis with subsequent delimitation of the genus. Among the traditionally used features for descriptions and delimitation of Nereis species are some that are highly variable, especially paragnath number. Bakken et al. (2009) made a useful revision of paragnath morphology and introduced new terminology to standardize descriptions. In addition to conical paragnaths, the species described here present other types of paragnaths that are not currently included in the diagnosis of the genus. Conical paragnaths are pointed to various degrees, being more acute in the maxillary ring, especially on area II. The pyramidal paragnaths in Nereisoligohalina and Nereisgarwoodi have quadrilateral bases but they can also be polygonal, having more defined surfaces in the latter species. Further, Nereisconfusa sp. n. apparently has smooth bars on area IV, but a closer inspection confirms that this is an artifact because the bars are formed by lateral and basal fusions of some small conical paragnaths (Fig. 6H); these modified structures were regarded as melted paragnaths (Bakken et al. 2009). However, Glasby et al. (2011) suggested limiting use of the term for conical paragnaths mounted on a plate-like basement as occurs in Neanthespachychaeta (Fauvel, 1918), and Villalobos-Guerrero and Carrera-Parra (2015) found paragnaths on a soft basement in Alittaacutifolia (Ehlers, 1901). Because neither a basement is present in Nereisconfusa sp. n., we suggest the term ‘merged’ for paragnaths fused at the base but without formation of a plate.


Redescriptions of Nereis oligohalina (Rioja, 1946) and N. garwoodi González-Escalante & Salazar-Vallejo, 2003 and description of N. confusa sp. n. (Annelida, Nereididae).

Conde-Vela VM, Salazar-Vallejo SI - Zookeys (2015)

Variation of Nereis species studied. NereisoligohalinaA, D, J–L, O, Q from ECOSUR–OH–P0760. NereisgarwoodiB, E from paralectotype ECOSUR 0066; I, M, R from ECOSUR P2834. Nereisconfusa sp. n. C, F–H, N, P from ECOSUR P2838. A–C Pharynges everted, dorsal view D–F Pharynges everted, ventral view G Pharynx everted, anterior view, showing merged paragnaths (arrows) H Close-up of merged paragnaths on area IV I–J Variations on area I K Variations on areas V and VI L Fingerprint-like pattern, dorsal view M–N Pigmentation patterns on anterior ends, dorsal view O Parapodial furrow in posterior end, lateral view (arrow indicates start) P Specimen on tube, dorsal view Q Parapodium from posterior chaetiger, anterior view R Ventral cirrus duplicated, chaetiger 5, anterior view. Scale bars: 0.5 mm (A–F, L); 1 mm (M–P); 0.1 mm (Q–R).
© Copyright Policy - creative-commons-attribution
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4591595&req=5

Figure 6: Variation of Nereis species studied. NereisoligohalinaA, D, J–L, O, Q from ECOSUR–OH–P0760. NereisgarwoodiB, E from paralectotype ECOSUR 0066; I, M, R from ECOSUR P2834. Nereisconfusa sp. n. C, F–H, N, P from ECOSUR P2838. A–C Pharynges everted, dorsal view D–F Pharynges everted, ventral view G Pharynx everted, anterior view, showing merged paragnaths (arrows) H Close-up of merged paragnaths on area IV I–J Variations on area I K Variations on areas V and VI L Fingerprint-like pattern, dorsal view M–N Pigmentation patterns on anterior ends, dorsal view O Parapodial furrow in posterior end, lateral view (arrow indicates start) P Specimen on tube, dorsal view Q Parapodium from posterior chaetiger, anterior view R Ventral cirrus duplicated, chaetiger 5, anterior view. Scale bars: 0.5 mm (A–F, L); 1 mm (M–P); 0.1 mm (Q–R).
Mentions: Although the species described here have more attributes than those included in the current diagnosis of the genus (Bakken and Wilson 2005), the generic diagnosis was not modified because it first requires a redescription of the type-species, and a phylogenetic analysis with subsequent delimitation of the genus. Among the traditionally used features for descriptions and delimitation of Nereis species are some that are highly variable, especially paragnath number. Bakken et al. (2009) made a useful revision of paragnath morphology and introduced new terminology to standardize descriptions. In addition to conical paragnaths, the species described here present other types of paragnaths that are not currently included in the diagnosis of the genus. Conical paragnaths are pointed to various degrees, being more acute in the maxillary ring, especially on area II. The pyramidal paragnaths in Nereisoligohalina and Nereisgarwoodi have quadrilateral bases but they can also be polygonal, having more defined surfaces in the latter species. Further, Nereisconfusa sp. n. apparently has smooth bars on area IV, but a closer inspection confirms that this is an artifact because the bars are formed by lateral and basal fusions of some small conical paragnaths (Fig. 6H); these modified structures were regarded as melted paragnaths (Bakken et al. 2009). However, Glasby et al. (2011) suggested limiting use of the term for conical paragnaths mounted on a plate-like basement as occurs in Neanthespachychaeta (Fauvel, 1918), and Villalobos-Guerrero and Carrera-Parra (2015) found paragnaths on a soft basement in Alittaacutifolia (Ehlers, 1901). Because neither a basement is present in Nereisconfusa sp. n., we suggest the term ‘merged’ for paragnaths fused at the base but without formation of a plate.

Bottom Line: Nereis oligohalina (Rioja, 1946) was described from the Gulf of Mexico, but it has been considered a junior synonym of Nereis occidentalis Hartman, 1945, or regarded as a distinct species with an amphiamerican distribution.In order to clarify these uncertainties, Nereis oligohalina is redescribed based on specimens from the Mexican Gulf of Mexico, including a proposed neotype; further, Nereis garwoodi is redescribed including the selection of lectotype and paralectotypes, and Nereis confusa sp. n. is described with material from the Gulf of California.A key for the identification of similar species and some comments about speciation in nereidid polychaetes are also included.

View Article: PubMed Central - PubMed

Affiliation: El Colegio de la Frontera Sur, CONACYT, Departamento de Sistemática y Ecología Acuática, Chetumal, México.

ABSTRACT
Type material of several polychaete species described by Enrique Rioja from Mexican coasts are lost, and the current status of some species is doubtful. Nereis oligohalina (Rioja, 1946) was described from the Gulf of Mexico, but it has been considered a junior synonym of Nereis occidentalis Hartman, 1945, or regarded as a distinct species with an amphiamerican distribution. On the other hand, Nereis garwoodi González-Escalante & Salazar-Vallejo, 2003, described from Chetumal Bay, Caribbean coasts, could be confused with Nereis oligohalina. In order to clarify these uncertainties, Nereis oligohalina is redescribed based on specimens from the Mexican Gulf of Mexico, including a proposed neotype; further, Nereis garwoodi is redescribed including the selection of lectotype and paralectotypes, and Nereis confusa sp. n. is described with material from the Gulf of California. A key for the identification of similar species and some comments about speciation in nereidid polychaetes are also included.

No MeSH data available.


Related in: MedlinePlus