Hesione, SAVIGNY IN LAMARCK, 1818,

Salazar-Vallejo, Sergio I., 2018, Revision of Hesione Savigny in Lamarck, 1818 (Annelida, Errantia, Hesionidae), Zoosystema 40 (12), pp. 227-325: 317-318

KEY TO SPECIES OF HESIONE SAVIGNY IN LAMARCK, 1818  Edit

1. Neuraciculae blackish .................................................................................................................................. 2

— Neuraciculae both pale, colorless; acicular lobes single, tapered; neurochaetal blades very long (6-12 times as long as wide) ........................................................................................................................... H. horsti  Edit n. sp.

2. Parapodia with acicular lobe single (lower tine, if present, reduced to a small round lobe; upper tine three or more than four times longer than lower one; see figs 7C, 8C, 10D) ............................................................ 3

— Parapodia with acicular lobe double (of similar length, or upper tine 2-3 times longer than lower one; see Figs 5D, 15C, 18C); neurochaetal blades bidentate ................................................................................................. 13

3. Neurochaetal blades bidentate ..................................................................................................................... 4

— Neurochaetal blades unidentate (subdistal tooth missing) .......................................................................... 12

4. Neurochaetal blades guards approaching distal tooth ................................................................................... 5

— Neurochaetal blades guards surpassing distal tooth; dorsal cirrophore twice as long as wide (living specimens with dorsal wide homogeneous brownish transverse bands) ....... H. eugeniae Kinberg, 1866  Edit (incl. H. cf. picta  Edit ex auct.)

5. Dorsal surface usually shiny, often areolated; dorsal cirrophore 2-3 times as long as wide (living specimens grayish) .................................................................................................... H. splendida Savigny in Lamarck, 1818  Edit

— Dorsal surface opaque; dorsal cirrophore variable (living specimens often with dorsal longitudinal brownish discontinuous bands) .................................................................................................................................. 6

6. Anterior eyes circular ................................................................................................................................... 7

— Anterior eyes as wide as long ..................................................................................................................... 11

— Anterior eyes as long as wide; dorsal surface smooth or with tubercles arranged into longitudinal series, at least along posterior chaetigers ................................................................................................... H. fitzhughi  Edit n. sp.

7. Acicular lobes tapered, without basal tine; dorsum rugose to microtuberculated, at least along posterior chaetigers ............................................................................................................................................................. 8

– Acicular lobes digitate, blunt, with a small basal round tine; dorsum smooth to slightly rugose, at least along posterior chaetigers .................................................................................................................................... 10

8. Neurochaetal blades 3-4 times as long as wide (living specimens with middorsal oval to foliose, as long as wide pale areas)................................................................................................. H. intertexta Grube, 1878  Edit restricted

— Neurochaetal blades up to 6 times as long as wide......................................................................................... 9

9. Acicular lobe triangular or basally swollen; neurochaetal blades 5-6 times as long as wide (living specimens with discontinuous longitudinal bands, and dorsal segmental, transverse pale, wide bands) .................................... ............................................................................................................... H. ceylonica Grube, 1874  Edit reinstated

— Acicular lobe digitate; neurochaetal blades 4-6 times as long as wide (living specimens with continuous longitudinal bands, and discontinuous reddish brown bands alternating with pale areas middorsally)..................... .............................................................................................................................................. H. uchidai  Edit n. sp.

10. Parapodial cirri with cirrostyles basally smooth; neurochaetal blades 4-6 times as long as wide ........................ ................................................................................................................ H. praetexta Ehlers, 1887  Edit reinstated

— Parapodial cirri with cirrostyles basally swollen; neurochaetal blades 4-5 times as long as wide ....................... .......................................................................................................................................... H. helenensis  Edit n. sp.

11. Acicular lobes blunt; subdistal tooth as wide as distal one, guard surpassing subdistal tooth (living specimens with middorsal pale areas) ..................................................................................... H. pantherina Risso, 1826  Edit

— Acicular lobes tapered; subdistal tooth thinner than distal one, guard approaching distal tooth (living specimens with middorsal blackish round spots) .......................................... H. panamena Chamberlin, 1919  Edit reinstated

12. Neurochaetal blades guards approaching distal tooth; neurochaetal blades 6-8 times as long as wide .............. ............................................................................................................................................ H. harrisae  Edit n. sp.

— Neurochaetal blades guards surpassing distal tooth; neurochaetal blades about 15 times as long as wide ......... ........................................................................................................................................... H. osbornae  Edit n. sp.

13. Subdistal tooth thinner or smaller than distal tooth ................................................................................... 14

— Subdistal tooth as wide as distal tooth ....................................................................................................... 19

14. Antennae long, 4-6 times as long as wide; neurochaetal blades with guards approaching subdistal tooth (living specimens with dorsal longitudinal brownish bands) ...................................................................................... .......................................... H. sicula  Edit delle Chiaje, 1830 reinstated (incl. H. steenstrupi de Quatrefages, 1866  Edit )

— Antennae short, smaller than interocular distance, about 3 times as long as wide ...................................... 15

15. Neurochaetal blades with guards approaching distal tooth ......................................................................... 16

— Neurochaetal blades without guards .......................................................................................................... 18

16. Acicular lobe as long as half chaetal fascicle width (living specimens with irregular transverse brown bands along tentacular segment and chaetigers 1-4 only) .................................................................... H. hartmanae  Edit n. sp.

— Acicular lobe as long as 1/3 chaetal fascicle width ...................................................................................... 17

17. Dorsum annulated, without longitudinal striae, smooth (living specimens with transverse dark brown bands along the whole body) .................................................................................................................................... ...................... H. picta Müller, 1858  Edit (incl. H. proctochona Schmarda, 1861  Edit and H. margaritae Hansen, 1882  Edit )

— Dorsum annulated and with longitudinal striae, rugose (living specimens with a complex, reticulate pigmentation pattern) ............................................................................................ H. reticulata von Marenzeller, 1879  Edit

18. Dorsal cirrophore as long as wide; prostomium rectangular; eyes well-defined (integument thin; living specimens with wide transverse red bands along chaetigers 1-6(7), progressively separated into two bands in following segments) ........................................................................................................................... H. beneliahuae  Edit n. sp.

— Dorsal cirrophore twice as long as wide; prostomium wider posteriorly; eyes poorly defined (integument thick; pigmentation unknown) ....................................................................................................... H. keablei  Edit n. sp.

19. Dorsum of preserved specimens with transverse dark brown bands ........................................................... 20

— Dorsum of preserved specimens colorless; acicular lobe with tines of different length ..................................... ............................................................................................................ H. pacifica McIntosh, 1885  Edit reinstated

20. Wide dark brown transverse band on chaetiger 2; chaetiger 1 mottled or pale; acicular lobe with tines of different length .................................................................................................................................................. 21

— Wide dark brown transverse band on chaetiger 1; chaetiger 2 mottled or pale; acicular lobe with tines of similar length ......................................................................................................... H. genetta Grube, 1864  Edit restricted

21. Longest tentacular cirri reach chaetigers 5-6; dorsal transverse band better defined along anterior margin ...... ............................................................................................................................................. H. paulayi  Edit n. sp.

— Longest tentacular cirri reach chaetigers 8-9; dorsal transverse band well defined along anterior and posterior margins ............................................................................................................................... H. mooreae  Edit n. sp.

Figures

FIG. 5. — Hesione beneliahuae n. sp., holotype, UF 658:A, living specimen, dorsal view, head to the right, B, anterior region, dorsal view;C, anterior end, oblique dorsal view; D, chaetiger 8, left parapodium, anterior view (inset: acicular lobe); E, same, blades of upper, medial and lower neurochaetae (inset: lower blade tip); F, posterior region, dorsal view. Scale bars: A, 3.5 mm; B, 1.8 mm; C, 0.5 mm; D, 0.4 mm; E, 25 µm; F, 1.5 mm.

FIG. 15. — Hesione genetta Grube,1867,specimen UF 81: A, anterior region,dorsal view;B, same,close up of anterior end (arrow points to left antenna);C, chaetiger 9, left parapodium, anterior view (inset: acicular lobes); D, same, neurochaetal blades; E, posterior region, dorsal view (right region removed for molecular studies). Scale bars: A, 1.5 mm; B, 0.6 mm; C, 0.3 mm; D, 20 µm; E, 1.8 mm.

FIG. 18. — Hesione hartmanae n. sp., holotype, LACM 10158: A, anterior region, dorsal view; B, prostomium, dorsal view (arrows point to antennae); C, chaetiger 8, right parapodium, anterior view (inset: acicular lobe); D, same, neurochaetal blades (insets: tips of blades); E, posterior region, dorsal view. Scale bars: A, 2.2 mm; B, 0.3 mm; C, 0.6 mm; D, 65 µm; E, 1.5 mm.