Wetlands Ecology and Management 10: 233–242, 2002.© 2002 Kluwer Academic Publishers. Printed in the Netherlands. 233

Polychaete assemblages inhabiting intertidal soft bottoms associated withmangrove systems in Coiba National Park (East Pacific, Panama)

Eduardo Lopez1,∗, Pedro Cladera1, Guillermo San Martın1, Antonio Laborda2 & M. TeresaAguado1

1Laboratorio de Biologıa Marina e Invertebrados, Departamento de Biologıa, Facultad de Ciencias, UniversidadAutonoma de Madrid, E – 28049, Spain; 2Departamento de Biologıa Animal, Facultad de Biologıa, Universidadde Leon, E – 24071, Spain; ∗Author for correspondence, Fax: (+34) 91 397 83 44, E-mail: eduardo.lopez@uam.es

Key words: community structure, intertidal, Polychaeta, tropical shores

Abstract

The Coiba National Park is located off the Pacific coast of Panama and includes several small islands and a largerone which gives its name to the park. A number of rivers in Coiba Island have well developed mangrove systemsat their mouths and two of these were selected for the present study: Santa Cruz and El Gambute. The first onecomprises an assemblage of Rhizophora mangle, Laguncularia racemosa and Pelliciera rhizophorae, and showsno evidence of recent human activity. The second one is a smaller forest, solely composed of short Rhizophoramangle trees, and is recovering from the impact of human activities.

During 1997, the tidal flats associated with each system were studied. To assess the polychaete distributionwithin each tidal flat, three transects were arranged from the low to the upper intertidal level. Every transect hadthree sampling sites: the first one was adjacent to the low water level, the second one at an intermediate point, andthe third one close to the high water level and the mangrove line. At each site, three randomly chosen samples ofsediment were taken for faunal study and a further one was collected for sedimentology study. The polychaeteswere identified to species or genus level. For each flat, a matrix summarizing the actual number of individuals ofeach species in every sample was created, and population density, species richness and diversity were computedfor each site. After matrix data had been transformed, a similarity analysis of the samples was carried out.

Introduction

Although the benthic communities from tidal flats arewell known for temperate areas of Europe and NorthAmerica, the knowledge of the organisms inhabitingsimilar environments of other regions of the world isless. Several works have dealt with the communitystructure of soft tidal bottoms from widespread trop-ical areas (Warwick and Ruswahyuni, 1987; Alongi,1989, 1990; Reise, 1991; Dittman, 1996). Morespecifically, the mangrove-associated tidal communit-ies have been studied from Indonesia (Sasekumar,1974; Frith et al., 1976), China (Hsieh, 1995), EastAfrica (Day, 1975; Ólafsson, 1995; Schrijvers et al.,1995; Guerreiro et al., 1996), Atlantic coast of Mex-ico (Hernández-Alcántara and Solís-Weiss, 1991) or

Australia (Hutchings and Recher, 1982; Wells, 1983;Dittman, 2000). The communities along the Pacificcoast of Central America and nearby areas have re-ceived little attention and, after the pioneering work ofHartmann-Schröder (1959), only a few studies havebeen carried out in this area (Dexter, 1979; Vargas1987, 1988a, b, 1996).

The Coiba National Park is located off the Pacificcoast of Panama (Figure 1), between 7◦ 10’ and 7◦53’ N and between 81◦ 32’ and 81◦ 56’ W, and in-cludes several small islands and a larger one, whichgives its name to the park. The tidal regime is semidi-urnal, ranging from –1 to 6 m. A number of rivers onCoiba Island have well developed mangrove systemsat their mouths and two of these were selected forthe present study: Santa Cruz and El Gambute. The

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Figure 1. A. Map of Central America showing the location of Coiba Island. B. Map of Coiba Island. C. Map of northern area of Coiba Island(squared on Figure 1 B) showing the location of the two tidal flats being studied.

first one is located within a cove on the NW coast ofthe island (Figure 1). This cove faces the open ocean,but its relatively narrow mouth and the presence ofa small island in front of it makes the hydrodynamiccondition more sheltered than might otherwise be ex-pected. The tidal flat comprises two different beaches(each one corresponding to a river mouth) that fuseinto one large tidal flat at low tide (Figure 2A). Asmall permanent ravine irrigates the first one, while thedischarge from the more southerly river is greater andmore constant. The associated forest is composed ofan assemblage of Rhizophora mangle, Lagunculariaracemosa and Pelliciera rhizophorae, and shows noevidence of recent human activity. The second tidalflat is located on the leeward side of Coiba Island(Figure 1); therefore, although open, its hydrodynamiccondition is sheltered. Due to human activities in thepast, the associated mangrove system is much smal-ler and composed solely of short Rhizophora mangletrees. A small river runs through the northern area of

this forest and its mouth is located on the edge of thetidal flat (Figure 2B).

The aim of this work is twofold: first, to findout from the faunal analysis whether a well definedpolychaete assemblage is common to all tidal flats inCoiba Island, and, second, to assess the existence of azonation pattern in the distribution of the polychaeteswithin these tidal flats.

Material and methods

The sampling was carried out in June 1997. To assessthe distribution of the polychaete species from the hightowards the low intertidal area, three transects wereselected on each tidal flat. Using a stratified randomsampling approach, the major intertidal gradient wascovered. Three sampling sites were arranged on eachtransect: the first one (site A) was close to the lowwater mark, the second one (site B) was at an inter-

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Figure 2. A. Map of Santa Cruz mangrove forest and its associatedtidal flat showing sampling site locations (Transects 1 to 3). B. Mapof El Gambute mangrove forest and its associated tidal flat showingsampling site locations (Transects 4 to 6). Scale bar = 500 m.

mediate point and the third one (site C) was at a pointnear high water level and close to the mangrove line(Figure 2). Three samples were taken at random ateach site; a further one was collected for sedimentolgyanalysis. The samples for faunal study consisted ofa 40 × 40 cm square area, removing sediment to adepth of 30 cm. The sedimentology samples consistedof 100 g of sediment.

The faunal samples were sieved (1 mm gaugemesh) and the material obtained was fixed and pre-

served in 10% formaline in seawater. Subsequently,the biological material was separated from the remain-ing sediment and sorted into the higher taxonomicgroups. The polychaetes were identified to species orgenus level. For each tidal flat, a matrix summariz-ing the actual number of individuals of each speciesin every sample was created, and the number of spe-cies, and the number of species and diversity (H’=Shannon index using log2) were computed for eachsample. Then, both tidal flats were characterized bytheir mean values for these features and by their mostcommon and frequent species. After transformation ofmatrix data (log10 (x+1) method), a similarity analysisbetween samples (aggregation by means of EuclideanDistances, linkage rule by UPGMA) was carried outusing the STATISTICA statistical package.

The sediment samples were dried and subsequentlysorted through a series of graded sieves (mesh gaugesin mm: 4, 2, 1, 0.5, 0.25, 0.125, 0.623) by shakingfor 20 minutes with an automatic shaker. Each sitewas characterized by its sediment type (particle sizecorresponding to Q50) making use of Larsonneur’stypologies (Larsonneur, 1977), and by its sortingcoefficient (So=

√Q75 /

√Q25), after Trask (1950).

Results

Sediment analysis

The tidal flat associated with Santa Cruz mangroveforest is composed of a quite homogenous sediment,where fine sand of moderate sorting is the most fre-quent sediment type (Table 1). On the contrary, theanalysis of the sediment of the tidal flat associated withEl Gambute showed a very irregular pattern of dis-tribution of the sediment types and sorting was quitepoor throughout the study area (Table 2).

Faunal analysis

The results of the faunal analysis are available in ap-pendix, where the actual number of individuals persample is given for each species. Seven of these spe-cies are likely to be new species and are currentlyunder study for description. Another four are new spe-cies for the area (west coast of Central America andMexico).

The polychaete fauna inhabiting the Santa Cruztidal flat (transects 1, 2 and 3) was quite poor andonly 252 individuals belonging to 26 species were col-lected. Several samples contained a low number of

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Table 1. Features of the samples from Santa Cruz tidal flat (Sediment type and sortingcoefficient are given only once for each site).

Sample Number of Number of H’ Sediment type Sorting coefficient

species individuals

1A1 3 7 1.38 Fine sand 1.53 (Moderate)

1A2 2 4 1 – –

1A3 2 8 0.54 – –

1B1 3 9 1.35 Fine sand 1.48 (Moderate)

1B2 2 10 0.88 – –

1B3 3 4 1.35 – –

1C1 3 3 1.58 Fine sand 2.38 (Poor)

1C2 0 0 – – –

1C3 2 4 0.81 – –

2A1 2 11 0.44 Fine sand 1.5 (Moderate)

2A2 5 13 1.7 – –

2A3 7 28 2.2 – –

2B1 2 8 0.95 Fine sand 1.43 (Moderate)

2B2 3 8 1.3 – –

2B3 2 8 0.81 – –

2C1 3 9 1.22 Silty sand 0.54 (Very good)

2C2 0 0 – – –

2C3 5 9 2.06 – –

3A1 8 17 2.66 Fine sand 1.44 (Moderate)

3A2 5 6 2.25 – –

3A3 11 22 2.64 – –

3B1 3 5 1.37 Fine sand 1.35 (Moderate/good)

3B2 2 6 0.65 – –

3B3 3 4 1.5 – –

3C1 8 19 2.8 Fine sand 1.37 (Moderate)

3C2 6 13 2.35 – –

3C3 8 17 2.53 – –

Mean 3.8 9.3 1.5

individuals and two were even defaunated (Table 1).Consequently, the mean values for species numberand individuals per sample were low (3.8 and 9.3,respectively). Four species can be considered to berelatively abundant (Appendix 1): Hemipodus cali-forniensis Hartman, 1938 (29.5% of the total num-ber of individuals), Orbinia johnsoni (Moore, 1909)(13.1%), Amastigos cf. acutus Piltz, 1977 (7.9%),Glycinoe armigera Moore, 1911 (7.2%) and Ninoedolicognatha Rioja, 1941 (6%). The first three specieswere collected only in this tidal flat, and were absentfrom the beach associated with El Gambute forest.Frequency values were very low; O. johnsoni (presentin 55% of the samples), H. californiensis (in 48%)and N. dolicognatha (in 33%) were the most frequent

species. The mean H’ value was moderate (1.5), but itranged from 0 up to 2.66.

El Gambute tidal flat (transects 4, 5 and 6) har-boured a richer polychaete population. The collectedindividuals numbered 478, belonging to 51 species,and the mean number of individuals and species persample were clearly higher (17.7 and 6.4 respect-ively), although figures showed a very wide range(Table 2); also the mean value for diversity was higher(2.1). The most abundant species were Mesochaetop-terus alipes Monro, 1928 (24.5% of the individuals),Heteromastus filiformis (Claparède, 1864) (10.6%),Scoloplos (S.) acmeceps Chamberlin, 1919 (7.5%) andLumbrineris crassidentata Fauchald, 1970 (6.2%). Inthis flat, frequency values were very low, too; themost frequent species were S. (S.) acmeceps (present

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Table 2. Features of the samples from El Gambute tidal flat (Sediment type and sortingcoefficient are given only once for each site).

Sample Number of Number of H’ Sediment type Sorting coefficient

species individuals

4A1 5 96 0.33 Medium sand 2.03 (Poor)

4A2 4 29 0.79 – –

4A3 7 7 2.81 – –

4B1 3 8 1.56 Silty sand 2.62 (Poor)

4B2 10 24 2.87 – –

4B3 9 22 2.73 – –

4C1 4 5 1.92 Pebbles > 2.75 (Very poor)

4C2 2 2 1 – –

4C3 3 3 1.58 – –

5A1 11 17 3.26 Medium sand 3.49 (Very poor)

5A2 7 12 2.69 – –

5A3 10 17 3.1 – –

5B1 2 2 1 Silty sand 1.86 (Moderate)

5B2 1 1 0 – –

5B3 4 8 1.81 – –

5C1 15 49 3.29 Medium sand 2.04 (Poor)

5C2 13 40 3.31 – –

5C3 8 30 2.67 – –

6A1 9 11 3.03 Silty sand 2 (Poor)

6A2 1 1 0 – –

6A3 9 11 3.03 – –

6B1 4 15 1.72 Coarse sand 3.92 (Very poor)

6B2 7 19 2.46 – –

6B3 8 13 2.65 – –

6C1 6 14 2.13 Coarse sand 2.79 (Very poor)

6C2 9 16 2.9 – –

6C3 3 6 1.46 – –

Mean 6.4 17.7 2.1

in 48% of the samples), L. crassidentata (44%), H.filiformis (in 40%), Scoloplos (Leodamas) sp. A (37%)and Notomastus hemipodus Hartman, 1945 (33%).

Assemblage structure

The dendrogram resulting from the classification ana-lysis (Figure 3A) pointed out the existence of threegroups of samples on Santa Cruz tidal flat. Somesamples from the lowest levels of the tidal flat (sites2A and 3A) formed the first cluster and the samplesfrom site 3C constituted the second one, both with lowaffinity. The remainder of the samples were groupedin the third cluster, where all the samples from sites1A and 2B and most samples from sites 1B and 2Aformed a clear sub-cluster of high affinity, confirming

that these four sites harboured very similar polychaetefauna.

On El Gambute tidal flat, the dendrogram resultingfrom the classification analysis (Figure 3B) revealedfour clusters of samples. The three samples from site5C constituted the first one, two samples from site 4B(4B2 and 4B3) formed a second one and some samplesfrom the lowest levels of the tidal flat (samples 4A1and 4A2) formed another cluster. The largest clusterwas composed of the remaining samples.

Discussion

The polychaete assemblages found in the two tidalflats clearly differed and, hence, the existence of a

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Figure 3. A. Dendrogram showing the cluster analysis grouping the samples from Santa Cruz tidal flat. B. Dendrogram showing the clusteranalysis grouping the samples from El Gambute tidal flat.

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unique polychaete assemblage in Coiba tidal flats canbe dismissed. This is consistent with the great differ-ences in sediment features. Whereas similar sedimentsoccurred throughout the tidal flat in Santa Cruz, thesediment of the beach associated with the El Gambuteforest changed from one site to the next, especiallywith regards to sorting coefficient. This feature re-vealed an unstable sedimentation condition, whichmight be caused by the sea currents or, rather, bythe seasonal differences in the associated river dis-charge. In spite of this, the number of species andindividuals collected in El Gambute was higher andthe mean diversity value was also somewhat higheron this tidal flat. The leeward location of El Gam-bute could be the reason for this, since its shelteredposition proved to be favourable for tropical intertidalcommunities (Alongi, 1989). In the same work, thisauthor stated that diversity values in tidal flats arelower near mangrove forest due to the higher concen-tration of mangrove-derived tannins. Similarly, lowerabundance values within the mangrove forest havebeen reported (Kolehmainen and Hilder, 1975; Wells,1983; Dittman, 2000), confirming the negative effectof mangrove detritus on infaunal abundance. Thus, theproportionally greater surface of mangrove forest as-sociated with Santa Cruz tidal flat and the presence ofa high tannin concentration within the sediment (ap-preciable by the red-brown color of interstitial water)could explain the lesser abundance values. Anyway,differences in ‘H’ values are less than might be expec-ted from differences in species richness, showing thatthe assemblage of Santa Cruz is well structured despiteits scarcity of species.

Whether associated with mangroves or not, the oc-currence or absence of zonation within tropical tidalflats has long been a matter of discussion. More orless definite zonation patterns, similar to those fromtemperate areas, have been recorded from the same(Dexter, 1979) or different geographic areas (Guer-reiro et al., 1996; Dittman, 2000). On the contrary,no clear zonation was observed on any of the Coibatidal flats, and no clear correlation can be observedwith any spatial feature (height over low water level,distance to freshwater stream or to mangrove line, . . .)when comparing the groups of samples on plots withtheir location in the field. Rather the reverse, a patchydistribution can be inferred. In this sense, our resultsare more in accordance with those for the Pacific coastof Costa Rica recorded by Vargas (1988b), who did notfind any zonal pattern on the distribution of intertidalmeiofauna but a patchy distribution.

Acknowledgements

Part of the present study was financially supportedby Spanish AECI (Agencia Española de CooperaciónInternacional) and Panamanian INRENARE (InstitutoNacional de Recursos Nacionales Renovables). Theauthors wish to express their gratitude to Dr SantiagoCastroviejo, from Real Jardín Botánico (Madrid), andto Narciso Bastida and Cesar Pecchio for their assist-ance and friendship as field guides. Dr José ManuelViéitez, from Universidad de Alcalá, and Dr SabineDittmann, from Zentrum für Marine Tropenökologie(Bremen), gave us useful advice regarding results in-terpretation. We also acknowledge Dr Francisco Gar-cía, from Universidad de Sevilla, as well as MaríaCapa and Elisa Roldan, from Universidad Autónomade Madrid, for their help in both sample collection andsorting.

Appendix

Polychete species collected from Coiba Island tidalflats. For each species the numbers of individuals aregiven between parentheses.

F. PhyllodocidaeEteone dilatae Hartman, 1936.- 6A1 (1)Phyllodoce lamelligera (Linnaeus, 1791).- 3C1 (1)

F. GlyceridaeGlycera americana Leidy, 1855.- 4A1 (1)Glycera cf. tesselata Grube, 1863 1.- 4C2 (1) / C3 (1)/ 5A1 (1) / C1 (1)Hemipodus borealis Johnson, 1901.- 3B1 (1) / C1 (1)Hemipodus californiensis Hartman, 1938.- 1A1 (4) /A2 (2) / A3 (7) / B1 (5) / B2 (7) / B3 (1) / C3 (1) / 2A1(10) / A2 (8) / A3 (13) / B1 (5) / B2 (5) / B3 (6)

F. GoniadidaeGlycinoe armigera Moore, 1911.- 2C1 (1) / C3 (1) /3B1 (3) / B3 (3) / C1 (4) / C3 (7) / 4B2 (1) / 5C1 (2) /C2 (4) / C3 (3) / 6A1 (1) / A3 (1) / B1 (3) / B3 (1)

F. NephtyidaeNephtys singularis Hartman, 1950.- 2A1 (1) / 3A1 (2)/ A2 (1) / A3 (1) / 4B2 (1)

F. HesionidaeGyptis brevipalpa (Hartmann-Schröder, 1959).- 4A3(1) / 6A3 (1)

F. SyllidaeExogone breviantennata Hartmann-Schröder, 1959.-6A3 (1)

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F. NereididaeLaeonereis culveri (Webster, 1879) 3.- 5C1 (4) / C2(2)

F. EulepethidaeGrubeulepis mexicana (Berkeley and Berkeley, 1939).-3B2 (5)

F. SigalionidaeSthenelais variabilis colorata Monro, 1924.- 3A3 (1)/ 4A2 (1) / B1 (2) / B2 (7) / B3 (6) / 5A1 (2) / A2 (2) /A3 (2)Thalenessa lewissii (Berkeley and Berkeley, 1939).-1A1 (1) / 2A2 (1) / A3 (1) / 3A3 (1)

F. OnuphidaeDiopatra ornata Moore, 1911.- 2A2 (2) / A3 (1) / 3A1(2) / A2 (1) / A3 (1) / 4B2 (1) / 5C1 (1) / 6B2 (1)Kinbergonuphis vermillioensis (Fauchald, 1968).-5A3 (2)Onuphis eremita parva Berkeley and Berkeley, 1941.-3A1 (1) / A2 (1) / 5A1 (1) / A3 (1) / 6A1 (1) / A3 (1)

F. EunicidaeMarphysa sanguinea (Montagu, 1815).- 5C1 (1) / 6C2(1)

F. LumbrineridaeLumbrineris crassidentata Fauchald, 1970.- 3A3 (1) /4A3 (1) / B3 (1) / 5A1 (2) / A2 (2) / A3 (1) / B1 (1) /C1 (10) / C2 (4) / C3 (2) / 6A1 (1) / A3 (3) / B1 (3) /B2 (3) / C1 (1)Lumbrineris platylobata Fauchald, 1970.- 3A1 (1) /4C1 (1) / 5A3 (4) / C2 (3) / 6C2 (2)Ninoe dolicognatha Rioja, 1941.- 1B3 (1) / 1C1 (1) /2C3 (2) / 3A1 (1) / A2 (1) / C1 (3) / C2 (3) / C3 (3) /4B2 (1) / 5A1 (1) / C3 (1)

F. ArabellidaeArabella mutans (Chamberlin, 1919).- 6A2 (1)Arabella semimaculata (Moore, 1911).- 4C1 (2) / C2(1) / 5B2 (1) / C3 (1) / 6A3 (1) / B2 (1)Drilonereis falcata Moore, 1911.- 5C2 (1) / 6C2 (1)Drilonereis nuda Moore, 1909.- 4C1 (1) / 6C1 (1)

F. DorvilleidaeSchistomeringos longicornis (Ehlers, 1901).- 6A3 (1)

F. SpionidaeCarazziella calafia Blake, 1979.- 6A1 (1)Microspio cf. pigmentata (Reish, 1959) 2.- 4B3 (2) /5C1 (1)

F. OpheliidaeOphelina cilindricaudata (Hansen, 1882).- 3C1 (2) /C2 (3) / C3 (2) / 5B3 (3)

F. CirratulidaeCaulleriella alata (Southern, 1914).- 4A3 (1)Chaetozone corona Berkeley and Berkeley, 1941.-5A1 (1) / 6C2 (5) / C3 (1)

F. OrbiniidaeLeitoscoloplos pugettensis (Pettibone, 1957).- 4B3 (2)/ 6A3 (1) / C2 (2)Leitoscoloplos fragilis (Verril, 1873).- 4B2 (1)Leitoscoloplos sp. 4.- 3C3 (1)Naineris sp. 4.- 5A3 (1)Orbinia johnsoni (Moore, 1909).- 1A1 (2) /A2 (2) /A3 (1) / B1 (3) / B2 (3) / 2A1 (1) / A3 (3) / B1 (3) / B2(2) / B3 (2) / 3A1 (6) / A2 (2) / A3 (2) / B1 (1) / B2 (2)Scoloplos (Leodamas) rubra (Webster, 1879).- 4A1(1) / 5A1 (1) / A2 (2) / A3 (3) / C1 (2)/ C2 (1) / C3(2) / 6B1 (2)Scoloplos (Leodamas) sp. A 4.- 1C1 (1) / 2C3 (1) /3C1 (4) / C2 (4) / 4B1 (3) / 5B3 (1) / C1 (1) / C2 (4) /C3 (6) / 6A1 (3) / B2 (3) / B3 (2) / C1 (1) / C2 (1)Scoloplos (Leodamas) sp. B4.- 6B2 (7) / B3 (1)Scoloplos (Leodamas) sp. C 4.- 4A3 (1)Scoloplos (Scoloplos) acmeceps Chamberlin, 1919.-1B3 (2) / 2A3 (1) / 3A3 (1) / C1 (3) / C2 (1) / C3(1) / 4A1 (1) / B1 (3) / B2 (4) / B3 (8) / 5A1 (1) / A3(1) / B1 (1) / C1 (3) / C2 (5) / C3 (5) / 6B2 (1) / B3 (1)/ C2 (2)

F. ParaonidaeAricidea lopezi Berkeley and Berkeley, 1956 3.- 5C2(1) / 6C2 (1)Aricidea cf. pacifica Hartman, 1944 6.- 1B1 (1) / 3C3(1) / 4A1 (1) / 5A2 (1) / 6A1 (1)Aricidea wassi Pettibone, 1965.- 2C3 (1) / 3A3 (1) /5A3 (1)Aricidea sp. 4.- 1C3 (3) / 2C1 (6) / 3C2 (1) / C3 (1)Levinsenia gracilis (Tauber, 1879).- 3C3 (1)

F. MagelonidaeMagelona sp. 4.- 2A2 (1) / A3 (3) / B2 (1) / 3A1 (3) /A3 (1)

F. CapitellidaeAmastigos cf. acutus Piltz, 1977 5.- 2A2 (1) / A3 (6) /3A1 (1) / 3A3 (11) / B1 (1)Dasybranchus lumbricoides Grube, 1878.- 6B3 (1)Heteromastus filiformis (Claparède, 1864).- 1C1 (1) /2C3 (4) / 4B3 (1) / 5B3 (1) / C1 (9) / C2 (10) / C3 (9)/ 6B1 (8) / B2 (3) / B3 (5) / C1 (1) / C2 (2) / C3 (2)Mastobranchus variabilis Ewing, 1984 3.- 4A2 (2)Notomastus hemipodus Hartman, 1945.- 4B1 (5) / B2(1) / B3 (1) / C1 (1) / C3 (1) / 5A1 (2) / C1 (1) / C2 (1)/ 6A3 (1) / B3 (1)Notomastus tenuis Moore, 1909.- 4A3 (1)

F. ChaetopteridaeMesochaetopteros alipes Monro, 1928.- 4A1 (92) / A2(25)Spiochaetopterus costarum (Claparède, 1870).- 5A1(1) / 5B3 (3) / C1 (2) / 6B1 (2)

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F. MaldanidaeEuclymene sp. 7.- 4A2 (1) / 5A3 (1) / 6C1 (6) / C2 (1)/ C3 (3)

F. PectinariidaePetta sp. 7.- 5C1 (1)

F. AmpharetidaeIsolda bipinnata (Fauchald, 1977).- 4C3 (1) / 5C1 (10)/ C2 (3) / C3 (3) / 6B3 (1) / C1 (4)

F. TrichobranchidaeTerebellides atlantis Williams, 1984 3.- 4B3 (1) / 6A1(1)

F. TerebellidaeGlossothelepus mexicanus Hutchings and Glasby,1986.- 4B2 (2)Lanicides taboguillae (Chamberlin, 1919).- 4B2 (1) /B3 (4)

F. OweniidaeOwenia fusiformis delle Chiaje,1844.- 2C1 (2) / 3C1(1) / C2 (1) / 4A3 (1)

F. SabellidaeChone minuta Hartman, 1944.- 4B3 (3)Fabricinuda limnicola (Hartman, 1951).- 4A3 (1) /5A1 (4) / A2 (3) / A3 (1)Megalomma pigmentum Reish, 1963.- 5C2 (1)

Notes to appendix:1 The sculpture of their proboscideal papillae is ob-lique instead of longitudinal.2 The specimens are very similar to original descrip-tions of M. pigmentata, but their prostomia lack thecharacteristic black pigmentation.3 The species has never been recorded in the regionnear the study zone (Pacific coast of Mexico and Cent-ral America), but no appreciable difference with thedescription was observed. To confirm these new re-cords, further studies (i. e. comparison with typematerial) are needed.4 It is likely to be a new species. Currently, it is understudy.5 They have 10 thoracic chaetigers, like the type seriesof A. acutus, but chaetigers 9 and 10 are not a trans-ition region. Instead, thoracic chaetigers are abruptlyreplaced by abdominal ones.6 Dorsum and sides show a red pigmentation. The an-tenna is very long, reaching chaetiger 8 or 9.7 Identification impossible due to the poor preserva-tion of the material.

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