Anterior regeneration in the polychaeteMarenzelleria viridis(Annelida: Spionidae)

Abstract

The objective of this study was to examine the regeneration capacity of the spionid polychaete Marenzelleria viridis from Long Island, New York. In the field,~7% of the worms exhibited regeneration of the anterior end. In the laboratory, worms were ablated at the 10th-50th chaetiger and their regeneration documented. Anterior morphogenesis was similar to that previously reported for spionids, with wound healing, blastema formation, differentiation of segments, and formation of feeding and sensory structures (mouth, palps, nuchal organs) occurring within 14 d. Unlike in some spionids, the segments do not appear to all form simultaneously from the blastema; rather, external differentiation of segments was observed from posterior to anterior on the regenerate. The number of segments replaced was equal to the number ablated for up to 10 segments. A maximum of 17 segments were replaced when 20-30 chaetigers were ablated, and the number replaced decreased to 14 when 40-50 chaetigers were ablated. Survival and normal growth of the worms decreased with more chaetigers ablated; a significantly higher number of worms died or grew abnormally with ≥30 chaetigers ablated, compared to worms with ≤20 chaetigers ablated. Members of M. viridis could be valuable model organisms in the study of the cellular mechanisms involved in regeneration, and further research on regeneration in the field should be completed.Additional key words: marine, northwest Atlantic, Polychaeta, regenerate, sublethal predation Invertebrate Biology 135(4): 357-369.

A new record of a cryptogenic Dipolydora species (Annelida: Spionidae) in South Africa

“…Although architomic division has been reported before in D. socialis based on lab experiments (Stock, 1964) this is the first field observation of the phenomenon in the species. Asexual reproduction via architomy has thus far only been recorded from six spionids, including D. socialis (Blake, 2006; David & Williams, 2012 b ; Whitford & Williams, 2016). Stock (1964) found that D. socialis can regenerate a maximum of eight chaetigers which was also confirmed from field observations in this study.…”

Development and sexual dimorphism of branchiae in Streblospio benedicti

“…The palps, a second set of head appendages in Streblospio , have been well studied with respect to feeding (Dauer, 1983, 1984, 1985, 1994, 1997, 2000; Dauer et al, 2003; Kihslinger & Woodin, 2000; Mahon & Dauer, 2005; Qian & Chia, 1997), regeneration (David & Williams, 2012; Dualan & Williams, 2011; Lindsay et al, 2007; Matthews & Hentschel, 2012; Whitford & Williams, 2016), systematics (Worsaae, 2001), the sensory nervous system (Faroni‐Perez et al, 2016; Forest & Lindsay, 2008), and female reproduction (Duchene, 2000; Rice, 1978; Rice et al, 2008; Williams, 2000; Zakas, 2022). Similar research on spionid branchiae is scant.…”

Mass Start or Time Trial? Structure of the Nervous System and Neuroregeneration in Pygospio elegans (Spionidae, Annelida)

“…Regeneration following injury and fragmentation (in the case of asexual reproduction) has been shown to follow similar morphogenetic patterns [3]. This advanced ability to regenerate has now been extensively explored in around 30 spionid species [5,6].…”

“…The tempo and duration of regeneration depend on the species, the size of the worm, its stage of development (larva, juvenile, adult), the temperature during experiments, and the ablated parts and the size of these parts [3,4,31,32]. Numerous investigations have been conducted on regeneration of various species of annelids [5,6,33,34], but there is much less research on nervous system regeneration [35]. Most of these studies focus on the general topology of the nervous system by labeling only acetylated α-tubulin [36,37] or by using the most common antibodies against 5-HT and FMRFamide [20,28,30,38,39].…”