Amphiduros fuscescens (Marenzeller, 1975)

Martin, Daniel & Romano, Chiara, 2021, Morphology and sexual dimorphism of living mature adults of Amphiduros fuscescens (Marenzeller, 1875) (Annelida, Hesionidae, Amphidurine), first reported for the Iberian Peninsula, Biodiversity Data Journal 9, pp. 66020-66020 : 66020

publication ID

https://dx.doi.org/10.3897/BDJ.9.e66020

persistent identifier

https://treatment.plazi.org/id/CC82D51B-BFDE-569C-8D43-2CC11EDFFA46

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scientific name

Amphiduros fuscescens (Marenzeller, 1975)
status

 

Amphiduros fuscescens (Marenzeller, 1975)

Materials

Type status: Other material. Occurrence: recordedBy: Daniel Martin and Manel Bolivar ; individualID: B214; sex: male; lifeStage: adult; preparations: relaxed with Thymol , fixed and preserved in ethanol 95%; associatedSequences: GenBank : MW135348 View Materials ; Taxon : scientificName: Amphiduros fuscescens; phylum: Annelida ; class: Polychaeta ; order: Phyllodocida ; family: Hesionidae ; Location : continent: Europe ; waterBody: Mediterranean Sea ; country: Spain; stateProvince: Catalunya; municipality: Blanes ; locality: Punta Santa Anna ; verbatimDepth: 6-7 m; verbatimLatitude: 41°40 ’26” N; verbatimLongitude: 2°48 ’07” E; verbatimCoordinateSystem: degrees minutes seconds; Event : samplingProtocol: Scuba diving; year: 2019; month: 4; day: 22; habitat: shallow sublittoral with boulders on mixed coarse sand and gravel; eventRemarks: the specimen was collected from the sea bottom, it was hidden below boulders; Record Level : institutionID: Museo Nacional de Ciencias Naturales ; institutionCode: MVCN; collectionCode: MNCN 16.01/ 18935 Type status: Other material. Occurrence: recordedBy: Daniel Martin and Manel Bolivar ; individualID: XX214; sex: female; lifeStage: adult; preparations: relaxed with Thymol , fixed in a 4% formalin/seawater solution, preserved in 70% ethanol; Taxon : scientificName: Amphiduros fuscescens; phylum: Annelida ; class: Polychaeta ; order: Phyllodocida ; family: Hesionidae ; Location : continent: Europe ; waterBody: Mediterranean Sea ; country: Spain; stateProvince: Catalunya; municipality: Blanes ; locality: Punta Santa Anna ; verbatimDepth: 6-7 m; verbatimLatitude: 41°40 ’26” N; verbatimLongitude: 2°48 ’07” E; verbatimCoordinateSystem: degrees minutes seconds; Event : samplingProtocol: Scuba diving; year: 2019; month: 4; day: 22; habitat: shallow sublittoral with boulders on mixed coarse sand and gravel; eventRemarks: the specimen was collected from the sea bottom, it was hidden below boulders; Record Level : institutionID: Museo Nacional de Ciencias Naturales ; institutionCode: MVCN; collectionCode: MNCN 16.01/ 18936 Type status: Other material. Occurrence: recordedBy: Xavier Salvador Costa; individualID: X13; sex: female; lifeStage: adult; preparations: fixed and preserved in 95% ethanol; Taxon : scientificName: Amphiduros fuscescens; phylum: Annelida ; class: Polychaeta ; order: Phyllodocida ; family: Hesionidae ; Location : continent: Europe ; waterBody: Mediterranean Sea ; country: Spain; stateProvince: Catalunya; municipality: Sant Feliu de Guixols ; locality: Cala Maset ; verbatimDepth: 5 m; verbatimLatitude: 41°47 ’11” N; verbatimLongitude: 3°02 ’42” E; verbatimCoordinateSystem: degrees minutes seconds; Event: samplingProtocol: Scuba diving; year: 2021; month: 1; day: 30; habitat: shallow sublittoral with boulders on mixed coarse sand and gravel; Record Level: institutionID: Museo Nacional de Ciencias Naturales ; institutionCode: MVCN; collectionCode: MNCN 16.01/18937 GoogleMaps GoogleMaps GoogleMaps GoogleMaps GoogleMaps GoogleMaps

Description

Diagnosis

Gyptini with orange/brown eyes, dispersed eye pigment, coalescing nuchal organs, inflated dorsal cirri, and reduced stout emerging acicular notochaetae.

Morphological Description

Body anteriorly and posteriorly tapered, ventral flattened (Fig. 1 View Figure 1 A-C). Prostomiurn roughly oval, anteriorly truncate, posteriorly with distinct median incision (Fig. 1 View Figure 1 A-E). Palpophores cylindrical, antero-ventrally inserted and palpostyles proximally inflated, distally tapered (Fig. 1 View Figure 1 D-E). Lateral antennae longer than palps, cylindrical, distally tapering, inserted below palps; central antenna much shorter than lateral antennae, distinctly pointed, inserted dorsally between anterior pair of eyes, ceratophore absent (Fig. 1 View Figure 1 D-E). Anterior pair of eyes larger than posterior pair; nuchal organs long, bordering lateral and posterior margins of prostomium, mid-dorsally not coalescing (Fig. 1 View Figure 1 D-E). Dorsal cirri segment 1-5 elongated and slightly inflated, with those on segment 2, 4 and 5 largest and longest (Fig. 1 View Figure 1 A-C). Dorsal cirrophores segment 1-5 longer than on following segments. The remaining dorsal cirri roughly alternating inflated, with round tips, dorsally orientated and thinner, with pointed tips, more laterally orientated (Fig. 1 View Figure 1 A-C and Fig. 2 View Figure 2 A-C). In living specimens, thicker long dorsal cirri tending to be elevated from body plan, slightly sinuose, directed backwards; thinner short dorsal cirri not elevated from body plan, straight and perpendicular to antero-posterior body axis. Ventral cirri of segment 1-4 much longer than following ones, with those on segment 1 slightly longer; remaining ventral cirri ventro-distally inserted on neuropodium, with small and indistinct cirrophores and short, digitiform, distally tapering, non-pointed cirrostyles (Fig. 2 View Figure 2 C and Fig. 3 View Figure 3 A). Neuropodia and neurochaetae from segment 5, notopodia and notochaetae from segment 6. Notopodial acicular prechaetallobes conical, pointed; notoaciculae single or with small accessory basal acicula; notochaetae all chambered, simple and very fine, with numerous capillaries with two rows of small teeth and 2-10 most ventral curved chaetae with distal serration on ventral side; emerging acicular chaetae absent (Fig. 3 View Figure 3 B). Neuropodial acicular prechaetal lobes conical, much longer and more prominent than notopodial ones, neuroaciculae single or with small accessory basal acicula. Neurochaetae all compound, numerous, with chambered shafts and unidentate tips of blades; chaetal length increasing ventrally to dorsally (Fig. 3 View Figure 3 B). Pygidium with pair of large inflated cirri, similar to smallest dorsal cirri; median papilla present (Fig. 2 View Figure 2 D).

Colour in living animals transparent orange, with characteristically transparent appendages having white, iridescent bands on cirrophores and on tips of cirrostyles, a middle orange band on cirrostyles and white pigment as spots and bands on lateral antennae, dorsal cirri and cirrophores and on enlarged, anterior ventral cirri; eyes brownish; gut region orange (Fig. 1 View Figure 1 A-C and Fig. 2 View Figure 2 A-C). Preserved animals pale yellowish, eyes dark brown, other pigmentation lost, except for orange patches on cirrostyles of dorsal cirri when preserved directly with formalin (Fig. 3 View Figure 3 C-D).

Male sexually dimorphic characters

Body bright orange, 36.3 mm long, 5.7 mm wide (without parapodia) at chaetiger 15, with 35 chaetigers (Fig. 1 View Figure 1 A). Ratio body width vs. body length 0.4. Width of the long dorsal cirri 0.75 mm wide (0.1 when divided by body width). Posterior pair of eyes clearly separated from anterior pair (Fig. 1 View Figure 1 A and D). Sperm light orange, accumulating in parapodia from chaetigers 8-36. Most anterior (i.e. palps, antennae and fists, small tentacular cirri) and most posterior (i.e. last dorsal cirri and anal cirri) appendages brightly pigmented (Fig. 1 View Figure 1 A and Fig. 2 View Figure 2 B-C).

Females sexually dimorphic characters

Female from Blanes with violet body, 34.3 mm long, 3.8 mm wide (without parapodia) at chaetiger 15, with 40 chaetigers (Fig. 1B). Ratio body width vs. body length 0.11. Width of the long dorsal cirri 0.39 mm wide (0.08 when divided by body width). Posterior pair of eyes almost coalescent with anterior pair (Fig. 1 View Figure 1 B and E). Oocytes dark violet, from chaetigers 10-38, non-restricted to parapodia, measuring 115-175 µm in diameter. Most anterior (i.e. palps, antennae and fists, small tentacular cirri) and most posterior (i.e. last dorsal cirri and anal cirri) appendages brightly pigmented (Fig. 1 View Figure 1 B, Fig. 2 View Figure 2 A and D).

Female from Sant Feliu with orange/violet body, 37.8 mm long, showing traces of regenerating posterior segments, 5.3 mm wide (without parapodia) at chaetiger 15, with 40 chaetigers (Fig. 1 View Figure 1 B). Ratio body width vs. body length 0.14. Width of the long dorsal cirri 0.42 mm (0.08 when divided by body width). Posterior pair of eyes almost coalescent with anterior pair (Fig. 1 View Figure 1 C). Oocytes dark violet, from chaetigers 9-31, restricted to parapodia, measuring 90-115 µm in diameter. Most anterior (i.e. palps, antennae and fists, small tentacular cirri) and most posterior (i.e. last dorsal cirri and anal cirri) appendages brightly pigmented (Fig. 1 View Figure 1 B, Fig. 2 View Figure 2 A, and D).

Distribution

Southern France, eastern Sicily, northern Adriatic, north Iberian Mediterranean, Gulf of Aqaba. Other reports must be checked, as they may correspond to closely related, but distinct species (see Discussion).

Habitat

Below stones, amongst coarse shell gravel, shell and muddy sand and amongst kelp holdfasts, from shallow intertidal and medio-littoral. The species has been reported up to 50 m depth; however, these deeper reports may correspond to different species (see Discussion). Our specimens were observed to quickly swim by waving their bodies when the boulders below which they were hidden were turned up. Such a quick swimming reaction was always addressed prior to hiding again below close boulders.

Kingdom

Animalia

Phylum

Annelida

Class

Polychaeta

Order

Phyllodocida

Family

Hesionidae

Genus

Amphiduros