Levinsenia

Lovell, Lawrence L. & Fitzhugh, Kirk, 2020, Taking a closer look: an SEM review of Levinsenia species (Polychaeta: Paraonidae) reported from California, Zootaxa 4751 (2), pp. 257-275 : 271-272

Key to the species of Levinsenia reported from California

1. 1A. Body very small (10–15 mm long, 0.10 mm wide), terminal sensory organ well developed, 4–8 pairs of truncate, heavily ciliated branchiae, acicular spines bent tipped with thick hoods.................................... L. barwicki n. sp.

1B. Body small to moderate size (15–30 mm long, 0.15-0.35 mm wide), terminal sensory organ not well developed, 5–36 branchial pairs, acicular spines not bent tipped, with fringe on convex side................................................ 2

2. 2A. Posterior acicular neurochaetae in multiple overlapping rows; vary in shape from longer, thinner, straighter to shorter, thicker more recurved; post-branchial notopodial with methyl green staining spots......................... L. kirbyorum

2B. Posterior acicular neurochaetae in single rows, uniformly shaped; post-branchial notopodia without methyl green staining spots............................................................................................... 3

3. 3A. More than 25 pairs of long, thin, tapering branchiae; posterior acicular neurochaetae thin, nearly straight distally; methyl green staining absent on any part of the body................................................. L. multibranchiata

3B. Fewer than 25 pairs of tapering, blunt-tipped branchiae; posterior acicular neurochaetae, thicker, recurved distally........ 4

4. 4A. Prostomium conical, with ‘ocular’ pigment (may fade); 5–9, and up to 20 branchial pairs; methyl green stain pre- and post-chaetal areas, speckled in prebranchial chaetigers; solid methyl green band in branchial region and 2–3 post-branchial chaetigers.................................................................................... L. oculata

4B. Prostomium triangular, longer than wide, without “ocular” pigment; 7–16 branchial pairs; ventral methyl green staining in branchial region............................................................................... L. gracilis