DNA-assisted identification of Caulerpa (Caulerpaceae, Chlorophyta) reduces species richness estimates for the Eastern Tropical Pacific Author Fernández-García, Cindy Escuela de Biología, Centro de Investigación en Ciencias del Mar y Limnología (CIMAR), Universidad de Costa Rica, San Pedro, San José, 11501 - 2060, Costa Rica. Author Wysor, Brian Department of Biology, Marine Biology & Environmental Science, Roger Williams University, 1 Old Ferry Road, Bristol, Rhode Island 02809, USA. Author Riosmena-Rodríguez, Rafael Programa de Investigación en Botánica Marina, Departamento de Biología Marina, Universidad Autónoma de Baja California Sur, Carretera al sur Km 5.5, La Paz, C. P. 23080, México. Author Salamanca, Enrique Peña- Departamento de Biología, Facultad de Ciencias Naturales y Exactas, Universidad del Valle, Cali, A. A. 25360, Colombia. Author Verbruggen, Heroen School of BioSciences, University of Melbourne, Victoria 3010, Australia. & Phycology Research Group, Ghent University, Krijgslaan 281 (S 8), 9000 Ghent, Belgium. text Phytotaxa 2016 2016-03-14 252 3 185 204 http://dx.doi.org/10.11646/phytotaxa.252.3.2 journal article 10.11646/phytotaxa.252.3.2 1179-3163 13676171 Caulerpa sertularioides (S.G. Gmelin) M.A. Howe 1905:576 ( Figure 7 C,D ) Type Locality: −“in coralliis americanis”, possibly tropical Atlantic America. Description: −Erect, light green thallus. Feather like assimilators, with a central rachis, generally unbranched, (0.2–) 1.5–1.6 (–5.8) cm high, (1.2–) 4.9–5.2 (–11.0) mm wide, but showing a reduction of the frond size in intertidal environments. Distichous subopposite rows of filiform ramuli that arise at acute angles and curve toward the apices. Stolons spreading, creeping (0.3–) 0.8–0.9 (–3.0) mm diameter, with highly branched rhizoids in sandy bottoms. FIGURE 6. Habit and frond morphology of of Caulerpa chemnitzia clade: (A,B) Unbranched C. chemnitzia ecad peltata (CFNI-662), arrow points diameter of the stolon (C,D) Branched C. chemnitziaecad peltata (CFMX-304), ( E,F) C. chemnitziaecad vanbosseae (GC- 132). Habitat: −attached to rock and other hard substrata such as, dead and live coral and coral rubble, sandy bottoms, intertidal to 23 m deep, more common between 4– 7 m . In intertidal, can be growing on rocks with medium-energy wave action. In Colombia , patches of this species have been found in estuaries. Distribution in the ETP: − Mexico : Nayarit , Colima , Guerrero , Oaxaca , Nicaragua : Chinandega , Costa Rica : Guanacaste , Isla del Caño, Panama : Golfo de Chiriquí , Golfo de Panama , Colombia : Bahía Málaga (Chocó), Nariño . This study confirmed the wide latitudinal distribution of C. sertularioides ( Figure 3 ) not only along the ETP, but also inside the Gulf of California, Mexico . This species is associated with rocky shores and subtidal environments, but mainlycovers sandy bottoms ( Fernández-García et al. 2012 ). References: − Taylor 1945 , Dawson 1962a , Dawson 1962b , Earle 1972 , Soto 1983 Glynn & Maté 1997 , Wysor 2004 , Fernández & Cortés 2005 , Bezy et al. 2006 , Fernández 2007 , Fernández & Alvarado 2008 , Fernández & Cortés 2009 , Smith et al. 2010 , Fernández-García et al. 2011 , Littler & Littler 2010. FIGURE 7. Habit and frond morphology: (A,B) C. serrulata (CFIC-919), (C,D) C. sertularioides (CFCR-813), (E,F) C. verticillata (CFES-005). Other remarks : In Costa Rica ( Fernández & Cortés 2005 ) and Panama ( Glynn & Maté 1997 , Smith et al. 2010 ) this species has exhibited seasonal bloom patterns. The alga has maintained high densities for periods of several years, covering up to 90% of the benthos in some regions ( Fernández-García et al. 2012 ). In the Mexican tropical Pacific, Pedroche et al. (2005) have reported the forms: C. sertularioides f. brevipes (Colima and Oaxaca states) and C. sertularioides f. longiseta (Oaxaca state), which according to Fernández-García et al. (2012) may represent morphological adaptations to variable substrata and/or depth ranges. On shallow and rocky depths assimilators tended to be smaller and or even absent and the stolons were thicker. At greater depths and in finer sediments, assimilators are longer and stolons were thinner with more branched rhizoids ( Fernández-García et al. 2012 ).