Barcoding the fishes of Mesoamerica and the Caribbean

0

100

200

300

400

500

600

700

800

900

1000

No. Individual by Region

San Juan

Chiapas-Nicaragua

Chiriqui

Bocas

Santa Maria

Chagres

Tuira

Atrato-San Juan

Grand Total

0

20

40

60

80

100

120

140

160

180

200

No. Families No. Genera No. Species Total No. Ind.

Fish Barcodes Submitted to BOLD

MF Submitted

FWF Submitted

Why barcode Neotropical fish?

•Leverage local enthusiasm for DNA-based scientific inference to promote ichthyological discovery

•Use ichthyological discovery and interest in Neotropical fish to accelerate molecular systematics training for Latin American scientists

•Promote phylogenetic analysis of Neotropical fish through availability of high-quality DNA

•BOLD facilitates collaboration among geographically dispersed investigators

•GENBANK barcodes provide an additional window into a student’s science

•COI barcodes provide an additional ~600 bp of DNA sequence data, which in combination with additional genes distributed around the mitochondrial molecule (e.g. cyt b and ATP synthase) increase likelihood of detecting pseudogenes and contribute to the 2000 bp “needed” for a robust phylogenetic estimate of mtDNA

relationship

Characidae - Astyanax (“aeneus”, includes Bramocharax) - Brycon (‘striatulus’ group, includes chagrensis, behreae, sp. nov. “Bocas”, guatemalensis) - Hyphessobrycon - Roeboides

Heptapteridae - Rhamdia guatemalensis (includes wagneri) - Rhamdia laticauda (includes reddelli, parryi, rogersi, cabrerai, nicaraguensis)

Gymnotidae - Gymnotus

Synbranchidae - Synbranchus + Ophisternon

Study taxa

Miller (1966), Myers (1966)Mesoamerica colonized by primary freshwater fishes following the Pliocene completion of the Panama land bridge. Evidence: Low species diversity of primary freshwater fish species in nuclear Mesoamerica (north of Lake Nicaragua) in comparison to secondary freshwater fishes (Cichlidae, Poecilidae, etc.).

Bussing (1976, 1985)Mesoamerica colonized by freshwater fishes in two waves: “Old Southern” (early Tertiary) and “New Southern” (Pliocene). Evidence: Broad distribution and species richness of “Old Southern” clades, in comparison to narrow, southern distribution and species poverty of the “New Southern” clades.

Testing the alternative hypotheses of Miller and Myers versus Bussing is of general interest for understanding the role that evolutionary time plays in:

• geographic range expansion following invasion

• speciation

• alternative outcomes in the evolutionary assembly of a biota

Marine Geminates

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1

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5

0.0000.002

0.0040.010

0.0300.050

0.0700.090

0.1100.130

0.1500.170

0.1900.210

0.2300.250

0.2700.290

Gymnotus

0

1

2

3

Marine Geminates

Rhamdia guatemalensis

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5

10

15

20

25

30

Brycon

0

1

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5

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9

Gymnotus

Rhamdia guatemalensis

Brycon

Roeboides

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1

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10

Roeboides

(10 genera)

R

ob

.

10 MY2 MY 20 MY3 MY1 MY

Pim

A.

As

t.

BR

W.

Hy

p.

Gy

m.

Sy

n.

Cy

p.

Bra

.

Ra

L.

Ra

G.

Pim

B.

FINAL CLOSURE OF THE PANAMA LAND BRIDGE: 3.1-3.5 MILLION

YEARS BEFORE PRESENT

BR

E.

5 MY

Relative Time Line

PRESENT

10 MY2 MY 20 MY3 MY1 MY

FINAL CLOSURE OF THE PANAMA LAND BRIDGE: 3.1-3.5 MILLION

YEARS BEFORE PRESENT

5 MY

Relative Time Line

PRESENT

Rhamdia guatemalensis

Brycon striatulus group

Late colonists with extreme ranges

10 MY2 MY 20 MY3 MY1 MY

FINAL CLOSURE OF THE PANAMA LAND BRIDGE: 3.1-3.5 MILLION

YEARS BEFORE PRESENT

5 MY

Relative Time Line

PRESENT

Brycon argenteus groupBrachyhypopomus

Early colonists with range expansions cut short

500 Km

Mexico

area ofmain map

LAKE N.

BRW 1

BRW chagres

BRW 2

BRW 3

BRW 4

Rio P. Chic o

Rio A c la

Rio Casjac a l

Rio Cuango

LAKE N.

Rio Acla

Rio P. Chico

Rio Casjacal

Rio Cuango

not shown

BRE 2

BRE 1

BRE acla

BRE p.chico

BRE tuira

BRE bayano

BRE 3

BRE atrato

BRE casjacal

BRE cuango

BRE patia

(b)

(c)

BRE

BRW

A Crude Estimate of the Expansionary Waves of Immigration Assumptions: molecular clock calibration = 3.6% Ks per million years P f , mean historical immigrant propagule (size N=300) K f , mean drainage carrying capacity (N=25,000) Duration of the expansionary waves represented by the polytomies for the Brycon striatulus lineage, approximately 100,000 years

f edge, the mean frequency of dispersal events at the leading edge of the colonizing wave

(BRW = 3600 years) f saturated, the mean frequency of events resulting in the replacement of a resident mtDNA

with that of immigrant’s

(K f /

Pf )

f edge = f saturated

In this Brycon example, the calculated value of f saturated equals 300,000 years, which is the mean time interval between the turnover of occupant lineages by immigrant ones.

500 Km

Mexico

area ofmain map

LAKE N.

BRW 1

BRW chagres

BRW 2

BRW 3

BRW 4

Rio P. Chic o

Rio A c la

Rio Casjac a l

Rio Cuango

LAKE N.

Rio Acla

Rio P. Chico

Rio Casjacal

Rio Cuango

not shown

BRE 2

BRE 1

BRE acla

BRE p.chico

BRE tuira

BRE bayano

BRE 3

BRE atrato

BRE casjacal

BRE cuango

BRE patia

(b)

(c)

BRE

BRW

• Miller and Myers vs Bussing: The former authors had it right and all primary fishes found in northern Mesoamerica dispersed from South America around the time of the Pliocene (~3 MYA) completion of the Panama landbridge.

• geographic range is not strongly influenced by the time since colonization of Mesoamerica.

• speciation is not evident in Mesoamerica primary freshwater fishes in spite of significant phylogeographic structure, phylogenetic evidence indicating that dispersal is not strongly limiting, and ‘experimental’ evidence (not shown) demonstrating that communities are not saturated.

• evolutionary assembly of the Mesoamerican freshwater fish fauna, and striking differences with South American ichthyofauna is explained, in part, by the late arrival of primary freshwater fishes to Mesoamerica.