Document Type

Article

Publication Date

1-2015

Publication Title

Bulletin of Marine Science

ISSN

0007-4977

Volume

91

Issue/No.

1

First Page

47

Last Page

61

Abstract

The crinoid order Cyrtocrinida is known mainly from Mesozoic fossils; its few surviving members, all from bathyal environments, are among the most peculiar living crinoids. Cyrtocrinids attributed to Holopus mikihe Donovan and Pawson, 2008, have been observed in large numbers via submersible off the western coast of Roatán, Honduras, on vertical and overhanging walls at depths between 430 and 640 m. Observations in 2012, 2013, and 2014 have permitted the first estimates of population structure, growth, and regeneration. Two size modes were observed; the flat barnacle-like “juvenile” stage resembles confamilial and co-occurring Cyathidium pourtalesiAméziane, 1999, whereas the larger “adults” elevate the crown on a stumplike calyx. The 99th percentile growth rate was 0.19 cm yr–1, giving a minimum predicted age of 16 yrs for the largest specimen and 8.7 yrs for the median specimen; the median growth rate was 0.04 cm yr–1, corresponding to 72 and 39 yrs. However, the slower rate of growth in juvenile compared to adult specimens means that these ages are underestimates; actual median age may be closer to 50 yrs. Arm regeneration rate is estimated at 0.6 cm yr–1, and 9.8% of adult individuals were visibly injured, giving an interval of about 1.4 yrs between arm loss events. No recruitment or mortality was observed, and aggregations of evenly-sized individuals were prevalent, consistent with sporadic local recruitment and mortality.

Comments

©2015 Rosenstiel School of Marine & Atmospheric Science of the University of Miami

Additional Comments

NSF grant #s: 1036219, 10366393; National Geographic Society Grant CRE Research Grant #: 9283-13

DOI

10.5343/bms.2014.1061

Peer Reviewed

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