Nereis alacranensis
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Ordo: Phyllodocida
Familia: Nereididae
Genus: Nereis
Name
Nereis alacranensis Ramírez-Hernández, Adriana, 2015 – Wikispecies link – Pensoft Profile
- Nereis alacranensis Ramírez-Hernández, Adriana, 2015, Zootaxa 4012: 157-163.
Materials Examined
Type material.Holotype: Atokous individual collected from Arrecife Alacranes, Yucatán, southern Gulf of Mexico, (CNAP – ICML: POH- 39 -002), Station 14 B (22 ° 24 ' 46 "N, 89 ° 39 ' 53 "W), 12 December 2009, 1 m, coll. V. Solís-Weiss. Paratypes: (CNAP – ICML: POP- 39 -004): 7 atokous individuals, two of them coated with gold for SEM studies, Station 14 B (22 ° 24 ' 46 "N, 89 ° 39 ' 53 "W), 12 December 2009, 1 m; 3 specimens, Station 14 (22 ° 24 ' 46 "N, 89 ° 39 ' 53 "W), 12 December 2009, 1 m; 1 specimen, Station 14 B (22 ° 24 ' 46 "N, 89 ° 39 ' 53 "W), 12 December 2009, 1 m; 1 specimen, Station 14 C (22 ° 24 ' 46 "N, 89 ° 39 ' 53 "W), 12 December 2009, 1 m. Museo Nacional de Ciencias Naturales de Madrid (MNCN): 5 atokous individuals, 2 specimens (MNCP 16.01/ 16646), Station 15 (22 ° 23 ' 44 "N, 89 ° 39 ' 5 "W), 12 December 2009, 1 m; 3 specimens (MNCP 16.01/ 16645), Station 14 B (22 ° 24 ' 46 "N, 89 ° 39 ' 53 "W), 12 December 2009, 1m. All paratypes collected by V. Solís-Weiss. Non-type material examined.25 specimens (CNAP – ICML: PO- 39 -032), 1 specimen, Station 14 (22 ° 24 ' 46 "N, 89 ° 39 ' 53 "W), 12 December 2009, 1 m; 18 specimens, Station 14 B (22 ° 24 ' 46 "N, 89 ° 39 ' 53 "W), 12 December 2009, 1 m; 2 specimens, Station 14 C (22 ° 24 ' 46 "N, 89 ° 39 ' 53 "W), 12 December 2009, 1 m; 4 specimens, Station 15 (22 ° 23 ' 44 "N, 89 ° 39 ' 5 "W), 12 December 2009, 1 m. All specimens collected by V. Solís-Weiss. Additional material examined.Nereis baolingi de León-González & Solís-Weiss, 2000: Paratype, UANL3982, western shores of the Baja California Peninsula, Mexican Pacific.
Description
Description.Holotype complete with 63 chaetigers, 28 mm long, 2 mm wide. Paratypes with 56–63 chaetigers, 17–28 mm long, 1–2 mm wide. Body thin anteriorly, gradually tapering posteriorly towards pygidium. Colour cream in preserved specimens. Prostomium pentagonal, as long as wide, anterior margin entire; two pairs of eyes round and large, arranged trapezoidally; pair of smooth tapered antennae situated at anterior end; one pair of palps with large palpophores and short cylindrical palpostyles (Fig. 1 A, 2 A). Peristomium longer than length of first chaetiger, as large as anterior and middle chaetigers; four pairs of tentacular cirri of unequal length, with distinct cirrophores; posterior dorsal tentacular cirri longest, reaching chaetiger 3. A peristomial ventral plate present, located in the external side of the peristomium; it is a brown coarse arc shaped plate, with numerous and irregular rigid wrinkles (Fig. 1 B, 2 B, 3 A, B). Proboscis with a pair of light brown dentate jaws, each with 7–9 teeth. Black paragnaths usually with a pointed tip on both maxillary and oral rings. Maxillary ring of pharynx with paragnaths arranged in discrete areas (Fig. 2 A, B): area I absent; area II with 4 conical paragnaths (3–5 in paratypes) in irregular arrangement; area III absent; area IV with 5 conical paragnaths (5–8 in paratypes) in a curved row. Oral ring with paragnaths: area V absent; area VI with 5 conical paragnaths (3–7 in paratypes) in irregular arrangement; areas VII to VIII with 7 conical paragnaths arranged in a single transverse row. First two parapodia uniramous; with notopodial dorsal ligules shorter than long dorsal cirri; with small, triangular prechaetal lobe and shorter, rounded postchaetal lobe; neuropodial ventral ligule long, conical; ventral cirri long (Fig. 1 D, 2 D). All following parapodia biramous (Fig. 1 E–G). From parapodium 3, long dorsal cirri and conical notopodial dorsal ligules with rounded tips; with long, conical notopodial ventral ligule (Fig. 1 E–G, 2 G). Neuropodia with ventral ligules and long ventral cirri, which are longer in posterior parapodia; with short, rounded pre- and postchaetal lobes. Notochaetae: only homogomph spinigers in anterior parapodia (Fig. 2 C); heterogomph and sesquigomph spinigers absent; from chaetiger 15, homogomph falcigers with short blades, entire distally, multidentate, with up to 7 small lateral teeth, first and subsequent lateral teeth much smaller than terminal tooth (Fig. 2 E, F). Sesquigomph falcigers absent. Number of notochaetae vary along body: 3–4 at parapodium 3, 5–6 at parapodium 10, about 3 around parapodium 25, and 2 around parapodium 50. Neurochaetae grouped in two clearly separate fascicles. Dorsal fascicle with heterogomph falcigers and all spinigers homogomph, 7–10 chaetae per fascicle; heterogomph falcigers with serrated blades, about 14–17 short, slender lateral teeth, with a curved terminal tooth (Fig. 2 H). Ventral fascicle with homogomph and heterogomph spinigers, and heterogomph falcigers; around 10–15 chaetae per fascicle, their number decreases towards the posterior region of body; heterogomph falcigers with about 15 lateral teeth, well separated between them, and a distal curved tooth, which is clearly thicker than lateral teeth (Fig. 2 I). Pygidium with a pair of long and slender anal cirri (1 mm) (Fig. 1 C).
Discussion
Remarks.Nereis alacranensis n. sp. is characterized by a peculiar brown coarse arc shaped plate in the external ventral region of the peristomium, which together with the lack of paragnaths in areas I, III and V, the presence of 3–7 cones in area VI, 7 cones in a transversal row in areas VII–VIII, and the short notopodial homogomph falcigers with up to 7 lateral teeth, clearly separate it from the other species of the genus (Table 1).
Etymology
Etymology. The new species is named after the marine region where it was found: Alacranes Reef National Park, southern Gulf of Mexico. Habitat. Intertidal (1 m), on dead coral rocks, associated to seagrasses and sponges.
Distribution
Distribution. Alacranes Reef, Yucatán, southern Gulf of México.
Discussion
Discussion. All of the species of Nereis are characterized by the presence of paragnaths in at least one of the areas of both pharyngeal rings and by having notopodial homogomph falcigers in posterior parapodia. However, due to the high number of species that share those characteristics (241 species), they have been assembled in several groups. Nereis alacranensis sp. n. belongs to the group lacking paragnaths in areas I and V of the pharynx, with cones in a single row or absent in areas VII and VIII, and short blades in notopodial homogomph falcigers. Only five other species share those morphological characteristics (Table 1): Nereis anoculopsis Fauchald, 1972, recorded in deep waters, and N. baolingi de León-González & Solís-Weiss, 2000, collected on the continental shelf, both from the Mexican Pacific (Fauchald 1972; de León-González & Solís-Weiss 2000), N. cirriseta Hutchings & Turvey, 1982, from Australia, N. eugeniae (Kinberg, 1866), widely distributed in the southeastern Pacific Ocean (Kinberg 1866; Ríos et al. 2003; Rozbaczylo et al. 2005), Falkland Islands (Monro 1936, Darbyshire 2014), and South Africa (Day 1960, 1967), and N. grayi Pettibone, 1956, from the northeastern Atlantic Ocean (Pettibone 1956; Day 1973; Gardiner 1976), and the Gulf of Mexico (Taylor 1984; Fauchald et al. 2009).
Morphological structures N. anoculopsis Fauchald, 1972N. baolingi de León- González & Solís-Weiss, 2000N. eugeniae (Kinberg, 1866)N. grayi Pettibone, 1956N. cirriseta Hutchings & Turvey,1982N. alacranensis n. sp.Area I0 0 0 0 0 0Area II4 cones in transverse row2 cones9–11 cones in two rows2–3 small cones2–7 cones in 1 or 2 oblique rows3–5 cones in diagonal row Area III0 0absent or 2–6 small cones in irregular row0 0, rarely 1 small cone0Area IV4 cones in group2 cones absent or grouped (0–18)10–13 cones in triangular group4–10 cones irregularly in oblique crescent5–8 cones in curved row Area V0 0 0–1 0 0 0Area VI0 0 3–6 cones in small group3–4 small cones3–6 cones in oval group or transverse row3–7 cones in irregular arrangement Area VII–VIII2 cones in transverse row7 cones in transverse row0–11 cones sparse in irregular row0 4–7 cones in transverse row7 cones in transverse row Blades of notopodial homogomph falcigers Short, with 6–7 thick teeth; similar along body Short with 3–4 short teeth; similar along body Short and smooth; similar along body Short and smooth; similar along body Short with several small bristle-like teeth; posterior falcigers with clearly elongate blades Short with up to 7 short teeth; similar along body Tentacular cirri Short (chaetiger 4)Short (chaetiger 2)Short (chaetiger 2)Long (chaetiger 8)Short (chaetiger 3)Short (chaetiger 3)Habitat On soft sediments; 1,632 m On rocky ledges and shingle; intertidal On soft sediments; intertidal to160 m On rocks; intertidal and sublittoral to10 m On dead coral rocks, associated with sponges and seagrasses; intertidal Distribution Mexican Pacific Mexican Pacific Strait of Magellan, Chile; Falkland Islands; Kerguelen Islands; South Africa Northwest Atlantic, Gulf of Mexico West and South Australia Southern Gulf of Mexico
The pharyngeal structure of N. eugeniae can be differentiated from all other species in this group by the presence of 9–11 paragnaths in area II, 2–6 small cones in area III, and no paragnaths in area IV. In other species, including, N. alacranensis n. sp., the maximum number of cones is 7 in area II, no paragnaths in area III, and at least 2 cones in area IV (Table 1). The morphological characteristics of N. eugeniae vary depending on the different authors’ descriptions, mainly when referring to the paragnaths’ distribution. However, thanks to the revision of that species by Darbyshire (2014), which integrates the information of Ehlers (1897), Monro (1930) and Hartman (1964, 1967), we know that, occasionally, up to 18 cones have been found in area III in this species. Notwithstanding, the morphological differences, between N. eugeniae and the new species are significant (Table 1).
Taxon Treatment
- Ramírez-Hernández, Adriana; Hernández-Alcántara, Pablo; Solís-Weiss, Vivianne; 2015: Nereis alacranensis, a new species of polychaete (Annelida, Nereididae) from Alacranes Reef, southern Gulf of Mexico, with a key to Nereis from the Grand Caribbean, Zootaxa 4012: 157-163. doi
This treatment was originally uploaded by Plazi, compare this treatment on Plazi. Unless this treatment has been substantially changed on Species-ID, Plazi requests to maintain a link back to the original repository.
