Maps
Locality Map
Locality map for Sistrurus miliarius (Western Pygmy Rattlesnake).
Map created 6 March 2024.
County Map
County map for Sistrurus miliarius (Western Pygmy Rattlesnake).
Map created 6 March 2024.
Historical Locality Map
Historical locality map for Sistrurus miliarius (Western Pygmy Rattlesnake). Black circles ( 
) represent records after 1986, blue squares ( 
) represent records between 1966 and 1986, orange triangles ( 
) represent records prior to 1966. Note that more recent records might conceal underlying older records.
Map created 6 March 2024.
Historical County Map
Historical county map for Sistrurus miliarius (Western Pygmy Rattlesnake). Black circles ( ) represent records after 1986, blue squares ( ) represent records between 1966 and 1986, orange triangles ( ) represent records prior to 1966. Note that only the most recent county record for each county is shown.
Map created 6 March 2024.
Ecological Drainage Locality Map
Ecological Drainage Units locality map for Sistrurus miliarius (Western Pygmy Rattlesnake).
Map created 6 March 2024.
Natural Divisions Locality Map
Natural Divisions and Sections locality map for Sistrurus miliarius (Western Pygmy Rattlesnake).
Map created 6 March 2024.
Major Watersheds Locality Map
Major Watersheds locality map for Sistrurus miliarius (Western Pygmy Rattlesnake).
Map created 6 March 2024.
Level I Ecoregion Locality Map
Level I Ecoregion locality map for Sistrurus miliarius (Western Pygmy Rattlesnake).
Map created 6 March 2024.
Level II Ecoregion Locality Map
Level II Ecoregion locality map for Sistrurus miliarius (Western Pygmy Rattlesnake).
Map created 6 March 2024.
Level III Ecoregion Locality Map
Level III Ecoregion locality map for Sistrurus miliarius (Western Pygmy Rattlesnake).
Map created 6 March 2024.
Level IV Ecoregion Locality Map
Level IV Ecoregion locality map for Sistrurus miliarius (Western Pygmy Rattlesnake).
Map created 6 March 2024.
Native Status
Sistrurus miliarius (Western Pygmy Rattlesnake) is native to Missouri.
Collection Summary
Sistrurus miliarius (Western Pygmy Rattlesnake) has a total of 128 valid, non-duplicated collections representing 16 counties and 79 localities. There are a total of 56 collectors and 74 collection dates for the species. This results in a total of 82 expeditions for the species, a measure of unique date / collector(s) combinations. The earliest collection year for the species in Missouri is 1900 and its most recent collection year is 2022. The earliest and latest collection dates (independent of earliest and most recent collection years) are April 1 and October 20, respectively. If you have a new record to report, read the New Records section of the FAQ.
Collection Summary by County
| County | Localities | Collections | Collectors | Dates | Expeditions | Earliest Year | Latest Year | |
|---|---|---|---|---|---|---|---|---|
 | Barry | 3 | 5 | 5 | 5 | 5 | 1939 | 2014 |
| Butler | 2 | 2 | 1 | 2 | 2 | 1960 | 1962 |
| Carter | 2 | 9 | 4 | 3 | 4 | 1940 | 2008 |
| Christian | 6 | 10 | 10 | 6 | 6 | 1967 | 2022 |
| Douglas | 2 | 2 | 3 | 2 | 2 | 2008 | 2008 |
| Howell | 3 | 3 | 4 | 2 | 3 | 1938 | 1969 |
| McDonald | 1 | 1 | 1 | 1 | 1 | 2011 | 2011 |
| Oregon | 3 | 3 | 2 | 3 | 3 | 1900 | 1961 |
| Ozark | 11 | 19 | 10 | 11 | 11 | 1956 | 1998 |
| Reynolds | 2 | 3 | 3 | 3 | 3 | 1933 | 1938 |
| Ripley | 3 | 3 | 5 | 3 | 3 | 2008 | 2009 |
| Shannon | 9 | 11 | 11 | 10 | 10 | 1939 | 2017 |
| Stone | 4 | 10 | 3 | 6 | 6 | 1907 | 1931 |
| Taney | 12 | 17 | 12 | 13 | 14 | 1954 | 2021 |
| Washington | 2 | 2 | 2 | 2 | 2 | 1951 | 1951 |
| Wayne | 13 | 27 | 10 | 15 | 17 | 1933 | 2019 |
Potential County Records
| Likelihood | County | Rationale | Ecoregion / Watershed | |
|---|---|---|---|---|
 | 2 | Iron | Same Level IV ecoregion, within 5 miles | St. Francois Knobs and Basins |
| 2 | Jefferson | Same Level IV ecoregion, within 5 miles | Meramec River Hills |
| 2 | Madison | Same Level IV ecoregion, within 5 miles | St. Francois Knobs and Basins |
| 2 | Saint Francois | Same Level IV ecoregion, within 5 miles | Meramec River Hills |
| 4 | Dent | Same Level IV ecoregion, within 10 miles | Current River Hills |
| 4 | Franklin | Same Level IV ecoregion, within 10 miles | Meramec River Hills |
| 4 | Greene | Same Level IV ecoregion, within 10 miles | Springfield Plateau |
| 4 | Texas | Same Level IV ecoregion, within 10 miles | Current River Hills |
| 4 | Texas | Same Level IV ecoregion, within 10 miles | White River Hills |
| 4 | Webster | Same Level IV ecoregion, within 10 miles | White River Hills |
 | 6 | Bollinger | Same Level IV ecoregion, within 20 miles | Black River Hills Border |
| 6 | Bollinger | Same Level IV ecoregion, within 20 miles | St. Francois Knobs and Basins |
| 6 | Lawrence | Same Level IV ecoregion, within 20 miles | Springfield Plateau |
| 6 | Newton | Same Level IV ecoregion, within 20 miles | Dissected Springfield Plateau-Elk River Hills |
| 6 | Stoddard | Same Level IV ecoregion, within 20 miles | Black River Hills Border |
| 6 | Wright | Same Level IV ecoregion, within 20 miles | White River Hills |
| 7 | Sainte Genevieve | Same Level III ecoregion, within 20 miles | Ozark Highlands |
 | 8 | Crawford | Same Level IV ecoregion, within 30 miles | Meramec River Hills |
| 8 | Dade | Same Level IV ecoregion, within 30 miles | Springfield Plateau |
| 9 | Phelps | Same Level III ecoregion, within 30 miles | Ozark Highlands |
| 9 | Saint Louis | Same Level III ecoregion, within 30 miles | Ozark Highlands |
Linnaean Classification
- Kingdom:
- Animalia - Animals
- Phylum:
- Chordata - Chordates
- Subphylum:
- Vertebrata - Vertebrates
- Class:
- Reptilia Laurenti, 1768 - Reptiles
- Order:
- Squamata Oppel, 1811 - Lizards and Snakes
- Suborder:
- Serpentes Linnaeus, 1758 - Snakes
- Family:
- Viperidae Bonaparte, 1840 - Asps and Vipers
- Genus:
- Sistrurus Garman, 1883 - Massasaugas and Pygmy Rattlesnakes
- Species:
- Sistrurus miliarius (Linnaeus, 1766) - Western Pygmy Rattlesnake
Recent Taxonomic Synonyms
(none)