A New Species of Myrianida Milne Edwards, 1845 
(Autolytinae: Syllidae: Annelida) from Luzon, Philippine Islands 
Patricia Alvarez-Campos i*, Guillermo San Martin i and Christina Piotrowski 2 
^ Universidad Autonoma de Madrid, Departamento de Biologia (Zoologia), 
Facultad de Ciencias, Cantoblanco, 28049 Madrid, Spain: ^ California Academy of Sciences, 
55 MusicConcourse Drive, Golden Gate Park, San Francisco, CA 94118, USA; E-mails: 
patricia.alvarez@iiam.es; gidllermo.sanmartin@uam. es; cpiotrowski@calacademy. org 
* Corresponding author. E-mail: patricia.alvarez@uam.es 
A new, brightly colored species of the genus Myrianida Milne Edwards, 1845 from 
the Philippine Islands is herein described. The new species is characterized by a 
striking color pattern, with a yellow body and alternating red bands, and with white 
antennae, tentacular cirri, first dorsal cirri, and anal cirri. The median antenna and 
nuchal epaulettes are very long.The pharynx exhibits single sinuation, and a trepan 
with 18-20 equal teeth in a single ring. The reproductive female stolons are 
described. Tlie phylogenetic position of the species within Myrianida is determined 
using molecular data, suggesting it is most closely related to the clade containing 
M. pachycera (Augener, 1913) and M. gidholmi Nygren and Pleijel, 2007. This is the 
first description of a well-characterized species of Myrianida from the Philippine 
Islands. 
Autolytinae is a well-delineated, monophyletic group of Syllidae Grube, 1845 (Nygren 1999; 
Nygren and Sundberg 2003; Nygren and Pleijel 2007; Aguado and San Martin, 2009; Nygren et al. 
2010; Aguado et al. 2012), easily recognizable by a lack of ventral cirri, presence of a sinuous phar¬ 
ynx, square-shaped proventricular muscle cells, and dimoiphic sexual reproduction (Nygren 2004; 
Nygren and Pleijel 2007; Nygren et al. 2010). Currently, the subfamily comprises 12 recognized 
genera (Nygren 2004; Nygren and Pleijel 2007; Nygren et al. 2010): Myrianida Milne Edwards, 
1845, Proceraea Claparede, 1864; Procerastea Langerhans, 1884; Virchowna Langerhans, 1879; 
Levidorum Hartman, 1967; Paraprocerastea San Martin and Aids, 1989; Epigamia Nygren, 2004; 
Imajimaea Nygren, 2004; Pachyprocerastea Nygren, 2004; Paraproceraea Nygren, 2004; Plani- 
cirrata Nygren, 2004; and Erseia Nygren, Sundkvist, Mikac and Pleijel, 2010. The genus Acrita- 
gasyllis, described by Lucas et al. (2010), ressembles the Autolytinae but it is considered as incer- 
tae sedis because its reproduction is still unknown. Autolytines reproduce by epitoky, which 
involves many morphological, physiological, and behavioral changes in ripe individuals (Malaquin 
1893; Potts 1911; Franke 1999; Nygren 1999, 2004; Nygren and Sundberg 2003, Nygren and Plei¬ 
jel 2007; Nygren et al, 2010; Aguado et al. 2012). They present two types of epitoky: Epigamy (the 
entire animal is transformed) and schizogamy (the posterior segments are transformed into epitok- 
ous individuals). Transformation occurs either as a single stolon at a time (scissiparity), or as sev¬ 
eral successive stolons in a row (gemmiparity) (Pleijel 2001; San Martin 2003; Nygren 2004; 
Aguado et al. 2007). Some species are brood caring, in which the female stolons can*y ventral egg- 
sacs (San Martin 2003; Aguado and San Martin 2009). 
Myrianida was redefined by Nygren (2004) as a large genus within the Autolytinae Langer¬ 
hans, 1879, comprising 33 valid species. It is characterized by the nuchal epaulettes, completely 
fused palps, three antennae, two pairs of tentacular cirri, cylindrical or flattened appendages, one 
or two ciliaiy bands on each segment, compound chaetae with bidentate blades, the proximal tooth 
typically larger than the distal one, thin bayonet-shaped dorsal simple chaetae, lack of ventral sim¬ 
ple chaetae, a slender pharynx with single or multiple sinuations, and a trepan with several equal 
145 
