Pseudoscalibregma Ashworth (1901) species

Mendes, Samuel Lucas Da Silva Delgado, Paiva, Paulo Cesar De & Rizzo, Alexandra E., 2024, New species of Pseudoscalibregma Ashworth, 1901 (Annelida: Scalibregmatidae Malmgren, 1867) from Brazil, Zootaxa 5399 (1), pp. 19-36 : 32-33

Key to Pseudoscalibregma Ashworth (1901) species , with type localities of each species

1. Peristomium papillated.................................... P. hartmanae ( Blake, 1981) ; Weddel Sea, Antarctica

- Peristomium without papillae........................................................................ 2

2(1). Nuchal crest present on prostomium posterior margin... P. bransfieldium ( Hartman, 1967) ; Bransfield strait, Antarctica.

- Prostomial nuchal crest absent....................................................................... 3

3(2). Spinous chaetae absent................................. P. glandulopodia Blake, 2023 ; Australia, Pacific Ocean.

- Spinous chaetae present............................................................................ 4

4(3). Lyrate chaetae from chaetiger 2...................................................................... 5

- Lyrate chaetae from chaetiger 3...................................................................... 8

5(4). Interramal papillae absent..................... P. papilia Sch ̧ller, 2008; South Sandwich Islands, Southern Atlantic.

- Interramal papillae present.......................................................................... 6

6(5). Spinous chaetae with bifurcated tips..................... P. parvum ( Hansen, 1879) ; Norwegian Sea, North Atlantic. Spinous chaetae with single pointed tips............................................................... 7

7(6). Rounded prostomium with short cylindrical horns; smooth proboscis; parapodial cirri initially rounded, progressively thinner and pointed on posterior chaetigers; chaetiger 1 biannulated, chaetigers 2-3 triannulated, then chaetigers quadriannulated........................................................ P. parapari sp. nov. South Atlantic

- Squared to trapezoidal prostomium with strong conical horns; papillated proboscis; all parapodial cirri digitate; all chaetigers biannulated................................. P. orientalis Imajima, 2009 ; Kashima Sea, Pacific Ocean.

8(4). Horns shorter than the half of prostomium width.............................. P. ermindae sp. nov. South Atlantic

- Horns longer than half prostomium width.............................................................. 9

9(8). Chaetiger 1 quadriannulated; parapodial cirri always smaller than parapodial lobes......................................................................................... P. usarpium Blake, 1981 ; Ross Sea, Antarctica.

- Chaetiger 1 triannulated or biannulated; parapodial cirri longer than parapodial lobes, at least on posterior chaetigers... ............................................................................................... 10

10(9). Squared prostomium; ocelli absent; chaetigers 1-3 biannulated, quadriannulated from chaetiger 4-16, then triannulated posteriorly................................................. P. palmeri Blake, 2015 ; East Antarctic Peninsula.

- Trapezoidal prostomium; ocelli present; chaetiger 1 biannulated, chaetigers quadriannulated from chaetiger 2 onwards..................................................................... P. magalhaesi sp. nov. South Atlantic