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Main Index
- Biodiversity Journal 2024
- Biodiversity Journal 2023
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Ulrich Kutschera
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Biodiversity Journal, 15 (2): 115-121
Ulrich Kutschera & Rajnish Khanna
The Significance of Darwin’s Origin of Species 1872 and ecology of salt-marsh plants in Northern California, USA
https://doi.org/10.31396/Biodiv.Jour.2024.15.2.115.121ABSTRACT
In 1872, the 6th (last) edition of Charles Darwin’s Origin of Species was published, wherein he had added a well-known section on Mivart’s criticism of 1871 concerning natural selection. Here, we describe Darwin’s ideas on “lower vs. higher organisms”, inclusive of his hypothesis of steady “perfection” and species co-existence during the evolutionary history of life. In addition, Darwin discussed evolution with reference to ecological interactions, proposed the concept of “competitive exclusion”, and, in our view, founded “evolutionary ecology”. These concepts were not addressed in the first, frequently quoted text of 1859. Therefore, we present Darwin’s ignored section with reference to a major recent paper on “Co-existence of plant species under harsh environmental conditions”, as well as our own observations on marsh vegetation in the San Francisco Bay Estuary. We conclude that “Darwin 1872” should be recognized as the definitive version of the “Species Book”, as recommended by the author himself and with reference to Letters published in the Darwin Correspondence Project-2023. -
Biodiversity Journal, 14 (4): 0537-0546
Ulrich Kutschera
The taxonomic status of the San Francisco Bay area Leech Helobdella triserialis (SF) (Annelida Hirudinida Glossiphoniidae) with notes on its ecology
https://doi.org/10.31396/Biodiv.Jour.2023.14.4.537.546
https://www.zoobank.org/89109D15-BF7A-47AD-B509-B875D6A981ECABSTRACT
Over the past decades, freshwater leeches of the genus Helobdella Blanchard, 1896 (Annelida: Hirudinida: Glossiphoniidae) have been used as model organisms for developmental studies. Notably, the species ”Helobdella triserialis US”, discovered during the 1970s in ponds in San Francisco (California , USA) was kept in lab-populations and served as representative of the genus, as documented in numerous publications. Here, I show that this enigmatic “San Francisco Bay area leech” has been misclassified and confused with the South American species H. triserialis (E. Blanchard, 1849), and later with H. papillata (Moore, 1952). Using specimens collected in Matadero Creek, Palo Alto (California , USA), novel morphological, anatomical, behavioral and molecular data (novel mitochondrial 618 bp-COI gene sequence) were generated. Based on these results, it is shown that this taxon represents a new North American species, described here as Helobdella farmeri n. sp. In addition, the occurrence of extant and extinct populations of Helobdella sp. in natural habitats of Northern California is documented over the past three decades. -
Biodiversity Journal, 11 (3): 689-698
Peter Hovingh & Ulrich Kutschera
Two new Helobdella species (Annelida Hirudinida Glossiphoniidae) from the Intermountain region of the United States, formerly considered as Helobdella stagnalis Linnaeus, 1758
https://doi.org/10.31396/Biodiv.Jour.2020.11.3.689.698
https://www.zoobank.org/References/8006dbb4-cf4f-4ce4-bad3-0a7bb4857fc3ABSTRACT
Two Helobdella stagnalis-like leech specimens (Annelida Hirudinida Glossiphoniidae) were histologically examined from Nevada in the Great Basin, and from Utah in the Colorado River Basin (USA) to determine whether or not their crops were similar to those in H. californica Kutschera 1988. The Nevada form was brown and with pigmentation patterns, whereas the Utah form was plain and white. The dorsoventral histological sectioning of these 3 specimens showed the Utah and Nevada forms had compact salivary glands, hitherto noted only in the South American Helobdella and Haementaria species. The pharynx of Nevada individuals was S-shaped, and in the Utah form the ejaculatory ducts formed a Gordian knot in the distal-most posterior region, further distinguishing these 2 intermountain Helobdella-isolates. Comparing these two taxa to other published Helobdella internal morphologies, two new species are proposed: Helobdella humboldtensis n. sp. from Nevada (size and pigmentation similar to H. californica) and Helobdella gordiana n. sp. from Utah, which resembles H. stagnalis from Europe. These findings suggest the Intermountain area may be a prime region to study the evolution of members of the Helobdella species complex.
- Biodiversity Journal 2024
- Biodiversity Journal 2023
- Biodiversity Journal 2022
- Biodiversity Journal 2021
- Biodiversity Journal 2020
- Biodiversity Journal 2019
- Biodiversity Journal 2018
- Biodiversity Journal 2017
- Biodiversity Journal 2016
- Biodiversity Journal 2015
- Biodiversity Journal 2014
- Biodiversity Journal 2013
- Biodiversity Journal 2012
- Biodiversity Journal 2011
- Biodiversity Journal 2010