# Presentation: 320197

## Morphological Variation Among Populations of the Federally Endangered Duskytail Darter, Etheostoma (Catonotus) percnurum

- Rebecca E. Blanton1, Robert E. Jenkins2, and Henry L. Bart, Jr.1
- 1Dept. Ecology and Evolutionary Biology,
-  Tulane University, New Orleans, LA
- 2Dept. Biology, Roanoke College, Salem, VA

## Taxonomic History

- Formerly *Etheostoma flabellare*, Fantail Darter
- First recognized as distinct species
- R. E. Jenkins 1976
- Diagnosed and described by Jenkins in 1994
- Freshwater Fishes of Virginia (Jenkins and Burkhead 1994)
*E. percnurum* – Duskytail Darter
- Reduced caudal barring relative to other closely related taxa

*E. percnurum*

*E. flabellare*

## Classification: Catonotus

## Distribution

- Modified from Jenkins and Burkhead 1994

- = **historically extirpated population**

## Morphological Variation

- Noted by Jenkins (Jenkins and Burkhead 1994)
- Differences in squamation and color
- Substantial between Copper Cr. and others
- Examined further by Eisenhour and Burr (2000)
- Found differences in:
- squamation and shape
- egg and ova counts
- nest size preference
- Hypothesized Big South Fork population was independent evolutionary unit

## Question

- Noted morphological variation along with high degree of isolation of populations
- Suggests each is likely on its own evolutionary trajectory
- Are disjunct populations morphologically diagnosable, warranting species-level recognition??

## Objectives

- Examine morphological variation:
- Determine taxonomic status of each population
- Describe species that warrant recognition
- Address conservation issues that may result from recognition of additional taxa

## Methods

## Methods

- Specimens
- Borrowed from museums and universities
- Variation examined using:
- Meristics
- Morphometrics
- Pigmentation
- Intra and Inter-population variation

## Methods

- MERISTICS:
- 26 counts
- Largely followed Hubbs and Lagler (1958),  Page (1983), and Jenkins and Burkhead (1994)
- 194 specimens examined from 6 populations and 2 drainages
- Males and females > 30 mm SL
- Tested for sexual dimorphism
- Males and females combined

## Methods

- MERISTIC DATA ANALYSIS:
- Univariate: Frequency distributions
- Multivariate: PCA (SYSTAT 5.2.1)
- 16 of 26 variables used for all individuals
- Factor scores plotted in Cricket Graph III
- Variables with component loadings >.50 were considered most important

**Notes:**
Multivariated analysis that allows you to examine variation in several characters at once to determine overall variation based on combination of cjaracters

Correlation matrix , non-transformed data 
Generatetes factror scores for each character of each individual  which can be plotted on a two - dimensional graph

The  graphs show clusters of individuals which allosw you to determine any seperation distinct groups.

Component loadings with abos. Vals. > . 35 indicated variables that contributed to seperation on the graphs.

First examined intradrainage variation, if no seperation, localitees w/I a draiange were amalgamated into larger groupings
Then could examine interdrainage veriation, again when no separation occurred, drainages amalgamated into larger groupings

## Methods

- MORPHOMETRICS
- Comparisons of body shape based on:
- Truss protocol (Bookstein et al., 1985) using 19 interlandmark distances
- 12 additional length/depth measurements (Hubbs and Lagler 1958)

*E. percnurum*_Copper Cr.

## Methods

- MORPHOMETRIC ANALYSIS
- Multivariate sheared PCA (Swofford; SAS 8.2)
- 12 variables and 123 individuals
- Univariate comparisons
- Measurements standardized with Standard Length
- Males and females analyzed separately
- Nuptial and non-nuptial males examined separately
- Included individuals > 35mm SL

## Methods 

- PIGMENTATION:
- Limited data due to lack of nuptial and live individuals
- Data examined for 4 pigmentation variables
- Jenkins previously examined other color and pigmentation characters of nuptial males (Jenkins and Burkhead 1994)
- ANALYSIS
- Univariate (frequency distributions, means)
- Descriptive comparisons

## Results

*MERISTICS*

## PCA: Meristics

**PC 2**

- PCA: *Meristics*

- Fewer:
- Pored Lateral Line
- Belly Scales
- Higher:
- Caudal Fin Rays

- Higher:
- Transverse Scales
- Caudal Peduncle Scales
- Scales Along D1 Base

## Squamation Along D1

**Little R.**

**Big South Fk.**
**Citico Cr.**
**Abrams Cr.**

**Copper Cr.**

## Results

- MORPHOMETRICS

## ResultsMorphometrics

- No variation between females from different populations
- Substantial overlap between non-nuptial males from different populations
- Nuptial males with high degree of body shape variation between populations

## Sheared PCA:  Nuptial Males

- Sheared PCA:  *Nuptial Males*

- Longer:          Pectoral Fin Length  Anal Fin Height

- Shorter:
- First Dorsal Height
- Second Dorsal Height
- Caudal Fin Length
- Longer:
- Pelvic insertion to
- Anal Fin insertion

## Results

- PIGMENTATION

## Means for Pigmentation Variables

- *No. caudal spots also examined but showed no variation

## Other Pigmentation DifferencesLittle R. vs. Copper Cr. Nuptial Males

- Pelvic fins best pigmented in Copper Cr.
- Rays of D2 more prominently marbled in Little R.
- Rays uniformly dusky in Copper Cr.
- Tessellations on Caudal Fin more intense in Little R.
- Tessellations lost in Copper Cr.

## Conclusions

- Substantial morphological variation among four extant populations
- Status of extirpated populations unclear due to low number of existing specimens
- Abram Creek and South Fork Holston River
- Grouped with closest geographic counterparts

## Conclusions

- Do any populations warrant species recognition?
- Little River *E. percnurum* diagnosed with % scale cover along D1 base
- also show distinct variation in morphometrics, and pigmentation
- Others diagnosed with combination of characters:
- Citico Creek – meristics and pigmentation
- Big South Fork – measurements
- Data needed for additional nuptial males
- Copper Creek –combination of characters

## Conclusions

- Each population should be recognized:
- Independent evolutionary units/species
- Conservation efforts should be structured to conserve all populations
- not just to maintain diversity, but because all are important *independent* units in the *E. percnurum* lineage

## Future Questions and Work

- Examine additional nuptial males from Citico Creek and Big South Fork
- Live and nuptial males for better pigmentation comparisons
- Diagnose and Describe
- Relationships within the *E.flabellare* group of *Catonotus*
- Are *E. percnurum* spp. monophyletic?
- Is there high levels of genetic structure within populations similar to that observed for its supposed sister taxon, *E.flabellare*?
- If so, important information for proper management and conservation

## ND2 Haplotype Locality Relationships

**ND2 Haplotype Locality Relationships**
***Etheostoma flabellare***

## Acknowledgements

- Institutions for loan of specimens:
- INHS
- UMMZ
- University of Tennessee
- Tulane Museum Natural History
- Southern Illinois University Carbondale
- American Museum Natural History
- National Museum Natural History
- Tulane University for facilities and equipment

## Questions

## Slide 31

## Classification

- Order: Perciformes
- Family: Percidae
- Genus: Etheostoma
- Subgenus: *Catonotus*

*Etheostoma percnurum*
*Duskytail Darter*

## Habitat

- Big South Fork, TN

- Citico Creek, TN

## Conservation Status

- Upon Description:
- Jenkins called for federal protection
- Relict distribution
- Extirpation of two populations
- Threats to habitat and water quality
- Listed 1993 as Federally Endangered (Biggins 1993)
- Recovery Plan developed 1994 (Biggins and Shute)

## Means of variables that loaded heavily on  sheared PC 3

- *Measurements standardized using SL

## ResultsMeristics

- Copper Creek and Citico Creek *E. percnurum* can be distinguished from one another based on meristics - no overlap in variation
- Both also show high degree of meristic differences from Little R. and Big South Fork individuals
- Little River and Big South Fork individuals with high degree of meristic similarity
- Little River diagnosible based on scalation along D1 base