Ampharete, Malmgren, 1866

Parapar, Julio, Moreira, Juan & Barnich, Ruth, 2019, A new species of Ampharete (Annelida: Ampharetidae) from the West Shetland shelf (NE Atlantic Ocean), with two updated keys to the species of the genus in North Atlantic waters, European Journal of Taxonomy 531, pp. 1-16 : 11-13

Key to North Atlantic species of Ampharete

Two keys are presented below as an update to those proposed by Parapar et al. (2012) for the North Atlantic species of Ampharete sensu Jirkov (2001) and Imajima et al. (2012). The keys now consider the two morphotypes of A. lindstroemi sensu Holthe (1986) and sensu Parapar et al. (2012), and include species described recently, namely A. undecima Alvestad, Kongsrud & Kongshavn, 2014 ; A. santillani Parapar, Kongsrud, Kongshavn, Alvestad, Aneiros & Moreira, 2018 as well as the new species described herein, Ampharete oculicirrata sp. nov. Both keys complement each other and reflect the traditional (Key 1) and a more recent way of constructing Ampharete keys (Key 2). Thus, Key 1 (following Day 1967; Holthe 1986; Hartmann-Schröder 1996) relies on meristic characters such as the number of thoracic and abdominal uncinigers, the number of papillae in pygidium and the length of paleae; whereas Key 2, (following Jirkov 2001; Jirkov & Leontovich 2013) emphasises other features, such as the shape of paleae, the shape of the rudimental notopodia of first two anterior abdominal uncinigers, and branchial arrangement. A synoptic table, summarising the diagnostic characters of all NE Atlantic species known prior to the new species described herein, is given in Parapar et al. (2018).

Key 1

1. Eleven thoracic uncinigers (TU). Small paleae present .................................................................... 2 – Twelve TU. Paleae present or absent ................................................................................................ 3

2. Twelve abdominal uncinigers (AU) ......................................................... A. borealis (M. Sars, 1856) – Fifteen to eighteen AU ........................................................................ A. octocirrata (M. Sars, 1835)

3. Paleae absent ............................................................................................. A. petersenae Jirkov, 1997 – Paleae present ................................................................................................................................... 4

4. Sixteen or more AU .......................................................................................................................... 5 – Fewer than sixteen AU ...................................................................................................................... 6

5. Sixteen to eighteen AU ............................................................................ A. goesi (Malmgren, 1866) – Twenty-four to twenty-eight AU ...................................................................... A. vega (Wirén, 1883)

6. Thirteen AU ...................................................................................... A. finmarchica (M. Sars, 1865) – Fewer than thirteen AU ..................................................................................................................... 7

7. Eleven AU ......................................................................................................................................... 8 – Twelve AU ........................................................................................................................................ 9

8. Pygidium with two long cirri and several small, low papillae. Prostomium and pygidial cirri with eyes .................................................................................................. Ampharete oculicirrata sp. nov.

– Pygidium with two short lateral cirri and several small, rounded papillae. No prostomial or pygidial eyes .............................................................. A. undecima Alvestad, Kongsrud & Kongshavn, 2014

9. Paleae shorter than distance between the two groups of branchiae ............. A. falcata Eliason, 1955 – Paleae longer than distance between the two groups of branchiae ................................................. 10

10. Paleae stout and gradually but quickly tapering terminally ................................................................ ...................................................................... A. villenai Parapar, Helgason, Jirkov & Moreira, 2012

– Paleae slender and evenly tapering ..................................................................................................11

11. Abdominal neuropodia with long dorsal cirrus ..................................... A. acutifrons (Grube, 1860) – Abdominal neuropodia with short dorsal cirrus ............................................................................. 12

12. Pygidium with two long cirri and several long papillae ............................... A. baltica Eliason, 1955 – Pygidium with two long cirri and several small papillae ............................................................... 13

13. Paleae long, widely surpassing the prostomium ................................................................................. ............................................... A. lindstroemi Malmgren in Hessle, 1917 sensu Parapar et al. (2012)

– Paleae short, not surpassing the prostomium .................................................................................. 14

14. Pygidial cirri with eyes; without dorsal neuropodial cirrus in posterior abdominal segments .......................................................... A. lindstroemi Malmgren in Hessle, 1917 sensu Holthe (1986)

– Pygidial cirri without eyes; with a short dorsal neuropodial cirrus in posterior abdominal segments ......................................................................................... A. santillani Parapar et al., 2018

Key 2

1. Paleae stout ....................................................................................................................................... 2 – Paleae absent or if present, slender and evenly tapering to long filiform tips .................................. 4

2. Paleae gradually but quickly tapering to comparatively long filiform tips (rarely missing) ........................................................ A. villenai Parapar, Helgason, Jirkov & Moreira, 2012

– Paleae abruptly tapering to very short filiform tips (usually missing) .............................................. 3

3. Thirteen abdominal uncinigers (AU) ................................................ A. finmarchica (M. Sars, 1865) – Sixteen to eighteen AU ............................................................................ A. goesi (Malmgren, 1866)

4. Rudimental notopodia of first two AU enlarged ............................................................................... 5 – All rudimental notopodia of similar size .......................................................................................... 6

5. Gap between branchial groups as wide as width of group, 12 AU .............. A. falcata Eliason, 1955 – Gap between branchial groups narrow or absent. 24–28 AU .......................... A. vega (Wirén, 1883)

6. Paleae at least twice as long or wide as the most developed notochaetae ........................................ 7 – Paleae delicate, only slightly longer than the following notochaetae or absent ..............................11

7. AU with long cirrus ............................................................................... A. acutifrons (Grube, 1860) – AU cirrus (if present) short ............................................................................................................... 8

8. Pygidium with two long cirri and several short papillae .................................................................. 9 – Pygidium with two long cirri and several long papillae ............................... A. baltica Eliason, 1955

9. Pygidial cirri with a pair of eyes ..... A. lindstroemi Malmgren in Hessle, 1917 sensu Holthe (1986) – Pygidial cirri without eyes ................................................................................................................ 0

10. Paleae short and stout, not surpassing anterior margin of prostomium .............................................. ........................................................................................................ A. santillani Parapar et al., 2018

– Paleae long and slender, clearly surpassing prostomium .................................................................... ............................................... A. lindstroemi Malmgren in Hessle, 1917 sensu Parapar et al. (2012)

11. Paleae absent; 12 thoracic uncinigers (TU) .............................................. A. petersenae Jirkov, 1997 – Paleae delicate, only slightly longer than the following notochaetae ............................................. 12

12. Eleven TU ....................................................................................................................................... 13 – Twelve TU ...................................................................................................................................... 14

13. Prostomium and pygidial cirri with eyes ......................................... Ampharete oculicirrata sp. nov. – No prostomial or pygidial eyes .................... A. undecima Alvestad, Kongsrud & Kongshavn, 2014

14. Three branchiae in each group arranged in line and fourth branchia posterior to this row ........................................................................................................... A. borealis (M. Sars, 1856)

– All four branchiae in each group arranged in line .............................. A. octocirrata (M. Sars, 1835)