Ampharetidae, Malmgren, 1866

Schiaparelli, Stefano & Jirkov, Igor A., 2021, Contribution to the taxonomic knowledge of Ampharetidae (Annelida) from Antarctica with the description of Amage giacomobovei sp. nov., European Journal of Taxonomy 733, pp. 125-145 : 138-139

Key to Ampharetidae genera occurring in Antarctica

In order to simplify the task of genera recognition of not trained people we have assembled a dichotomic key hoping that this would speed the recognition of the different Antarctic ampharetid genera.

1. Three or four anterior segments with vertical rows of minute acicular chaetae ................................. ...................................................................................................... Melinninae Chamberlin, 1919 ...2

– Minute acicular chaetae absent ................................................ Ampharetinae Malmgren, 1866 …3

2. Hooks (usually one pair) and dorsal crest (usually one and dentate) behind the branchiae present ........................................................................................................ Melinna Malmgren, 1866

– Hooks absent, dorsal crest present .............................................. Melinnides Wesenberg-Lund, 1950 (= Melinnantipoda)

– Hooks and dorsal crest absent ............................................................... Melinnopsis McIntosh, 1885 (= Amelinna , Melinnexis , Melinnopsides )

3. Buccal tentacles attached outside the mouth, methylene blue staining pattern of ventral glandular shields well marked ............................................................. Noanelia Desbruyères & Laubier, 1977

– Buccal tentacles attached inside the mouth (seldom may be everted), methylene blue staining pattern of ventral glandular shields poor marked ......................................................................................... 4

4. Prostomium Amphicteis -like: with prominent straight transversal nuchal ridges; middle lobe anteriorly more of less incised, usually with pair of longitudinal ridges; rudimental notopodia AU1 several times smaller than normal thoracic ................................................. Amphicteis Grube, 1850

– Prostomium Ampharete or Amage -like: trilobed, without prominent nuchal organs or ridges; middle lobe anteriorly rounded; rudimental notopodia AU1 several times smaller normal thoracic or absent ................................................................................................................................................ 5

– Prostomium without lobes, without prominent nuchal organs or ridges ........................................ 13

5. Middle lobe of prostomium anteriorly incised or with horns ( Fig. 1 A–B) ...................................... 6

– Middle lobe of prostomium anteriorly rounded or pointed .............................................................. 8

6. Abdominal neuropodia with very long cirri, longer than width of segment ...................................... .............................................................................................................. Samythopsis McIntosh, 1885 (= Neopaiwa , Paiwa, Weddelia )

– Abdominal neuropodial cirri, if present much shorter than width of segment ( Fig. 1G ) ................. 7

7. All abdominal neuropodia, including AU1 pinnuli ( Fig. 1G ), no more than 16 AU .......................... ...................................................................................................................... Amage Malmgren, 1866 (= Egamella , Mexamage , Paramage , Phyllampharete )

– All abdominal neuropodia pinnula, except AU1, neuropodia AU1 tori (like thoracic), more than 20 AU ......................................................................................................... Grubianella McIntosh, 1885

8. Distinct transversal dorsal ridge between TC3 and TC4 present ........................................................ ................................................................................................... Melinnampharete Annenkova, 1937 (= Eusamytha Hartman, 1967 non McIntosh, 1885, Eusamythella , Neosamytha )

– Dorsal ridge absent ........................................................................................................................... 9

9. One, usually from 5 th (4 th– 6 th) to the last pair of posterior notopodia slightly shifted dorsally and connected by low ridge .......................................................................... Anobothrus Levinsen, 1884

– One pair of posterior notopodia (last, 2 nd or 3 rd from last) flattened and shifted dorsally .................. ...................................................................................................................... Sosane Malmgren, 1866

– Posterior notopodia neither flattened, nor shifted dorsally, ridges also absent ............................... 10

10. 1 st segment with ‘horns’ .................................................................. Abderos Schüller & Jirkov, 2013

– 1 st segment without ‘horns’ ..............................................................................................................11

11. Lower lip enlarged, longitudinally grooved ............................................... Lysippe Malmgren, 1866 (= Lysippides , Paralysippe , Pseudampharete , Pterolysippe , Samytha )

– Lower lip not enlarged .................................................................................................................... 12

12. A pair of nephridial papillae medially behind the branchiae. Paleae well developed, paleal chaetae bigger then most developed notochaetae (paleae of species outside Antarctic may be smaller or even absent) .................................................................................................... Ampharete Malmgren, 1866 (= Asabellides , Parampharete , Pseudosabellides , Pterampharete , Sabellides ,? Amythasides )

– Nephridial palillae medially behind the branchiae absent ( Fig. 4C ). Paleae absent ........................... ....................................................................................................................... Amythas Benham, 1921

13. Two last pairs of notopodia (or only second counting from the back) slightly shifted dorsally and connected by low, transverse ridges ............................................................. Zatsepinia Jirkov, 1986

– Dorsally shifted notopodia and dorsal transverse ridges absent ..................................................... 14

14. Prostomium with pair of tranversal nuchal organs ......................................................................... 15

– Prostomium without nuchal organs ............................................. Glyphanostomum Levinsen, 1884

15. The shape of neuropodia slightly changed along the body ( Fig. 5B ) ....... Phyllocomus Grube, 1877 (= Shistocomus,? Amphisamytha )

– Neuropodia of thorax, AU1, and AU2 are tori, the rest are abdominal pinnuli, change is well marked .................................................................................................... Neosabellides Hessle, 1917

Figures

Fig. 1. A, C–I. Amage giacomobovei sp. nov., morphology. A. Paratype (MNA-07931). C–E, G–H. Paratype (MNA-06377). F, I. Paratype (MNA-07931). B. Amage auricula Malmgren, 1866, SP- 22 74, 74.633º, -164.500º, 465 m; arrows indicate the well-developed NO. A–B. Antero-dorsal view of prostomium. C. Buccal tentacles. D. Lateral view. E. Ventral view. F. Dorsal view of middle notopodia. G. Ventral view of last thoracic and first abdominal parapodia. H. Ventral view of middle thorax, showing details of staining pattern. I. Dorsal view of posterior end. Abbreviations: see Material and methods.

Fig. 4. Amythas membranifera Benham, 1921, morphology (MNA-07940). A–C. Lateral, ventral and dorsal views. D. Dorsal anterior end with a close-up view of the branchiae. E. Ventral view of the anterior end showing the mouth. F. External surface of the tube wall. G. Living specimen still embedded in the tube, partially cut with scissors before the extraction of the specimen. Scale bars = 10 mm.

Fig. 5. Amythas membranifera Benham, 1921 and some other Ampharetidae Malmgren, 1866, morphological features. A. Lateral view of A. membranifera (MNA-07490). B. Antero-ventral view of A. membranifera (MNA-07939). C. A. membranifera, dorsal view, showing places of branchostyles attachments and their origin (MNA-07935). D–I. Lateral view of last TC and anterior AU, showing change of neuropodial shape at thorax/abdomen border in different species of Ampharetidae. D. A. membranifera (MNA-07935). E. A. membranifera (MNA-07940). F. Phyllocomus sovjeticus (Annenkova, 1937), Aniva Bay, Japan Sea. G. Samythella elongata Verrill, 1873, R/V “Vitjaz”, station 5624, 45º26′ N, 154º12′ E, depth 5200 m. H. Ampharete finmarchica (M. Sars, 1865), R/V “Schmidt”, station 26.9301, 69.91667° N, 41.98333° E, depth 107 m. I. Amage auricula Malmgren, 1866, Ice station SP-22, st. 74, 74.633° N, -164.500° E, depth 465 m. J–L. Uncini of A. membranifera. J. From TU1. K. From AU1. L. From AU2 (last). Abbreviations: p = pinnuli; t = tori.