Anamobaea orstedii Kroyer , 1856,

Tovar-Hernandez, Maria Ana Ana, Garcia-Garza, Maria Elena & de Leon-Gonzalez, Jesus Angel, 2020, Sclerozoan and fouling sabellid worms (Annelida: Sabellidae) from Mexico with the establishment of two new species, Biodiversity Data Journal 8, pp. 57471-57471: 57471

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http://dx.doi.org/10.3897/BDJ.8.e57471

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scientific name

Anamobaea orstedii Kroyer , 1856
status

 

Anamobaea orstedii Kroyer, 1856 

Anamobaea orstedii  Anamöbæa Ørstedii

Anamobaea orstedi.  - Humman and Deloach 2001: 155; San Martín et al. 1994: 556, fig. 1A-I; Tovar-Hernández and Salazar-Vallejo 2006: 27-30, figs. 1-2.

Materials

Type status: Other material. Occurrence: catalogNumber: UANL 8133; recordedBy: Luis Fernando Carrera-Parra, Isabel Cristina Molina-Acevedo, Tulio Fabio Villalobos-Guerrero, Sergio I. Salazar-Vallejo; individualCount: 8; sex: Hermaphrodite; lifeStage: Adult; reproductiveCondition: Ripe; Taxon: phylum: Annelida; class: Polychaeta; order: Sabellida Levinsen, 1883; family: Sabellidae Latreille, 1825; genus: Anamobaea Krøyer, 1856; specificEpithet: orstedii Krøyer, 1856; Location: higherGeography: Atlantic Ocean; continent: America; waterBody: Gulf of Mexico; islandGroup: Sistema Arrecifal Veracruzano; country: México; countryCode: MX; stateProvince: Veracruz de Ignacio de la Llave; municipality: Veracruz; locality: Isla Verde ; maximumDepthInMeters: 1 m; decimalLatitude: 19.201191; decimalLongitude: -96.065768; Identification: identifiedBy: María Ana Tovar-Hernández; Event: samplingProtocol: By hand; eventDate: 27March 2015; year: 2015; month: 03; day: 27; habitat: Dead coral; Record Level: language: Spanish; institutionID: Universidad Autónoma de Nuevo León; collectionID: Colección Poliquetológica, Universidad Autónoma de Nuevo León; institutionCode: UANL; collectionCode: UANL, NL INV 0002-05-09GoogleMaps 

Description

Figures 1-5

Body shape and size. Specimens fairly large and plump on thorax, flattened dorso-ventrally in thorax (Fig. 2View Figure 2 B), pyriform abdomen in transversal section (Fig. 3View Figure 3 K). Body length 10-42 mm (n = 5, all lacking posterior abdomen), width 1.5-4 mm.

Radiolar crown. Length 6-17 mm with 15-20 pairs of radioles. Base of radiolar crown (basal lamina) smooth, long, as long as the length of eight thoracic segments in largest specimens. Erect, prominent dorsal and ventral flanges (Fig. 2View Figure 2 A-F and Fig. 3View Figure 3 A-B). Dorsal flanges forming a broad and deep canal from the base of dorsalmost radioles until base of posterior peristomial ring collar (Fig. 2View Figure 2 C and Fig. 3View Figure 3 B). Ventral flanges with an anterior digitiform lobe overlapped (Fig. 2View Figure 2 A) and exposing the base of parallel lamellae. Radioles united by a palmate membrane as long as two times the length of base of crown or basal lamina (Fig. 2View Figure 2 F). Radiolar skeleton composed of 12-16 cells in cross section at the base (Fig. 3View Figure 3 F), then decreasing in number towards mid-radiolar length (Fig. 3View Figure 3 J). Longest pinnules located at three quarters of the radiolar crown length. Radiolar tips filiform, occupying the space of 5-8 pinnules, without flanges (Fig. 4View Figure 4 H). Ocelli in both sides of the outside of radioles (Fig. 3View Figure 3 G-I). Dorsal most radioles with ocelli in groups of 15-22: basal ocelli distributed in two irregular rows (Fig. 3View Figure 3 H), distal ocelli forms only one row (Fig. 3View Figure 3 I). Ventral radioles with 5-10 ocelli in a single row. Dorsal lips long, erect, triangular (Fig. 3View Figure 3 E) with mid-rib (radiolar appendage). Dorsal pinnular appendages present, short. Dorsal lips longer than palmate membrane, reaching the basalmost radiolar ocelli. Ventral lips small, folded and joining radiolar lobes near origin of first ventral radiole. Ventral radiolar appendages absent.

Peristomium  . Anterior peristomial ring high, as long as the length of three thoracic segments, with rounded margin (Fig. 4View Figure 4 A-B, crown removed). Posterior peristomial ring collar: dorsal margins shallow, not fused to faecal groove (Fig. 3View Figure 3 B); ventral margins forming two nearly triangular lappets (Fig. 2View Figure 2 A and D), not overlapped (whereas relaxed or contracted). Parallel lamellae and ventral sacs present (Fig. 3View Figure 3 D). Ventral sacs rounded, inflated and exposed outside ventral basal flanges of crown, in some specimens full of sand (Fig. 3View Figure 3 A and D). Dorsal margin of anterior peristomial ring exposed above collar margin (posterior peristomial ring), triangular, divided by faecal groove (Fig. 3View Figure 3 B).

Thorax. Chaetigers very numerous (20-54 chaetigers). Ventral shield of collar rectangular, longer and broader than following shields (Fig. 2View Figure 2 A). Collar chaetae arranged in a bunch (Fig. 4View Figure 4 A) of short, spine-like with symmetrical hoods (Fig. 4View Figure 4 D). Ventral shields of chaetigers 2-8 rectangular, swollen (Fig. 2View Figure 2 A). Superior notochaetae spine-like, short, 3-4 per group (Fig. 5View Figure 5 A). Inferior notochaetae paleate, symmetrical (Fig. 4View Figure 4 E) or asymmetrical (Fig. 5View Figure 5 B), arranged in two transverse rows, each row with 3-4 chaetae (Fig. 5View Figure 5 A). Tori not contacting ventrals shields (Fig. 2View Figure 2 A). Uncini avicular, with minute, equal-size teeth covering half of the crest (Fig. 5View Figure 5 E), breast well developed, handle as long as two times the length of crest (Fig. 4View Figure 4 I). Companion chaetae with symmetrical tips as teardrop-shaped membranes (Fig. 4View Figure 4 I, Fig. 5View Figure 5 D), shaft not longer than uncini. Posterior segments with brown blood vessels dorsally, forming rectangular, sinuous nets seen in both alive and fixed material (Fig. 3View Figure 3 C).

Abdomen. Number of chaetigers not fully determined (incomplete specimens, the longest with 124 segments). Segments with brown blood vessels dorsally, forming rectangular, sinuous nets (Fig. 3View Figure 3 C). Neurochaetal fascicles in two transverse rows. Anterior abdominal segments with anterior and posterior rows of paleate chaetae with dentate mucros (Fig. 4View Figure 4 G and Fig. 5View Figure 5 C), mucros short (as long as paleae width) being fragile and broken in many paleae (Fig. 5View Figure 5 C) and modified, elongate, narrowly-hooded chaetae (Fig. 4View Figure 4 K). Posterior abdominal segments with paleae with long mucros (more than three times the width of paleae) (Fig. 4View Figure 4 G) and modified, elongate, narrowly-hooded chaetae. Uncini avicular, with 30-37 rows of equal-sized teeth covering 3/4 of the crest length (Fig. 5View Figure 5 F), breast well developed (Fig. 4View Figure 4 J), handles as long as crest. Pygidium not examined (specimens lacking the last segments of abdomen, near pygidium).

Variation. One large specimen (44 thoracic chaetigers, 3.5 mm width) with a regenerating radiolar crown: it is short, measuring only 6 mm in length with 18 pairs of radioles, all unequal in length. This regenerating crown has a palmate membrane well developed and dorsal radioles with rows of 8-14 ocelli, whereas ventral radioles have 5-6 ocelli.

Colour in live specimens. Radiolar crown with red and white bands in situ (Fig. 1View Figure 1). Under light microscopy, base of radiolar crown translucent. Basal half of radiolar crown red with a translucent palmate membrane and red radiolar ocelli. Distal half of radiolar crown with alternate white and red bands. Ventral lappets of posterior peristomial ring collar and lateral margin of anterior peristomial ring red. Body yellow with ventral shields and lateral margins of the body whitish. Anterior thoracic segments with narrow, red, transversal lines between each torus.

Colour in preserved specimens. Palmate membrane white. Basal half of crown with radioles brown to orange containing rows of brown ocelli. Distal half of crown with whitish radioles. Radiolar tips white. Ventral lappets with large, orange spots each. Whitish ventral sacs. Segments from mid-thorax with two brown, sinuous blood vessels dorsally forming a nearly-rectangular shape. Some abdominal segments with brown, sinuous blood vessels forming a rectangular shape dorsally.

Tubes. Tubes embedded in dead coral seem like wooden trunks with a strong consistency, composed of an external wide bark-like layer and several thin, golden internal layers.

Diagnosis

Base of the radiolar crown smooth (basal lamina) with prominent, erect, dorsal and ventral flanges. Collar chaetae arranged in a bunch. Ocelli in both sides of the outer margin of radioles. Dorsal-most radioles with ocelli in groups of 15-22 (basal ocelli distributed in two rows, distal ocelli forms only one row). Ventral radioles with 5-10 ocelli in a single row. Simultaneous hermaphrodite.

Biology

Ripe simultaneous hermaphrodites were found with female and male gametes within the coelom of abdominal segments and also attached to the internal tube layer (Fig. 4View Figure 4 K-L). Oocytes are equal in size and spermatozoa with spherical nucleus and rounded cap-like acrosome.

Taxon discussion

According to Fitzhugh (1989), members of Anamobaea  , Hypsicomus  and Notaulax  , have a low anterior margin of the anterior peristomial ring, of even height all around. However, in the description provided here for Anamobaea  , this feature is interpreted as high (as long as three thoracic segments), with distal margin rounded once crowns were removed to properly examine the peristomium (Fig. 4View Figure 4 B-C). In addition, Perkins (1984) [figs. 25E-F and 35E-F], illustrates anterior peristomial rings of Notaulax bahamensis  Perkins, 1984 ( Perkins 1984) and N. nudicollis  ( Krøyer, 1856) ( Krøyer 1856) similar to that described here for Anamobaea  . Consequently, a re-examination of this feature is needed in Hypsicomus  , as well as in other members of Notaulax  .

Tovar-Hernández and Salazar-Vallejo (2006) reported a radiolar skeleton composed of 6-7 cells in cross-section and thorax with 32-55 chaetigers. In the present study, a small variation was found: 12-16 cells at the base of radioles and then decreasing in number towards medium radiole length. Specimens here reported have 20-54 thoracic chaetigers. Ventral lips were incorrectly shown by Tovar-Hernández and Salazar-Vallejo (2006) in their figure 1B (as vl). These structures correspond to ventral sacs, not ventral lips. The ventral lips are small, folded and joining radiolar lobes near the origin of first ventral radiole.

In addition, it should be noted that the spelling of the species name orstedii  has previously been incorrect in a number of publications (misspelled as " orstedi " instead the original " orstedii  ") in Fitzhugh (1989) [p. 74], San Martín et al. (1994) [p. 556], Tovar-Hernández and Salazar-Vallejo (2006) [p. 27], Dean (2012) [p. 65] and Capa et al. (2019) [p. 191].

Detailed information about eye and ocelli types found in A. orstedii  was provided by Bok et al. (2016): eye type S (scattered ocelli on both sides of each radiole) and ocelli type 4 (four-cell forming the ocellus).

Reproductive information is absent for Anamobaea  . In this study, the presence of simultaneous hermaphroditism is confirmed in A. orstedii.  Brooding within the tube of the radiolar crown was not observed. Broadcast spawning is supported by sperm morphology (spherical heads).

Most of the sabellid species present a thorax consisting typically of eight chaetigers ( Fitzhugh 1989), but there is a remarkable exception in Anamobaea  , where a long thorax consisting of 20-54 chaetigerous segments in Anamobaea orstedii  (this study) or 74 in A. phyllisae  has been reported, being the highest number of thoracic segments reported nowadays in Sabellidae  ( Tovar-Hernández and Salazar-Vallejo 2006). Other exceptions are represented by members of Perkinsiana  , which may have 19 thoracic segments as in P. anodina  or 24 in P. longa  ( Capa 2007).

Perhaps the presence of a long thorax in Anamobaea  and some species of Perkinsiana  is related to their mode of life in corals. Perkinsiana anodina  was described as sclerozoan of dead coral from Western Australia, where there were large granite boulders with small colonies of live and dead corals on them ( Capa 2007). It was also found in Tiger Island (Indonesia) surrounded by tissue of a mushroom coral where their tubes form straight protuberances on the scleractinian coral surface ( Tovar-Hernández et al. 2020). As corals provided refuge to worms in addition to that provided by their own tubes, it is probable that worms present a high growth and longevity as demonstrated in other infaunal, tube worms of corals such as the serpulid Spirobranchus corniculatus  (Grube, 1862) ( Grube 1862) with an estimated longevity of 15-20 years or the sabellariid Idanthyrsus  sp., with eight years of longevity ( Nishi and Nishihira 1999, also see their fig. 1 where a boring Notaulax  was sketched). The tube ultrastructure of A. orstedii  has a regular plywood microstructure which is lamellar in cross-section ( Vinn et al. 2018), whereas the tube wall of Perkinsiana anodina  is dense, non porous, with sparsely spaced three different sets of fibres ( Tovar-Hernández et al. 2020). This indicates that inhabiting with coral has had no effect on the tube microstructure of the species, possibly because P. anodina  did not communicate with the host coral through its tube wall.

Kingdom

Animalia

Phylum

Annelida

Class

Polychaeta

Order

Sabellida

Family

Sabellidae

Genus

Anamobaea

Loc

Anamobaea orstedii Kroyer , 1856

Tovar-Hernandez, Maria Ana Ana, Garcia-Garza, Maria Elena & de Leon-Gonzalez, Jesus Angel 2020
2020
Loc

Anamobaea orstedii

Kroyer 1856
1856