Original paper
Towards a biogeography of Mastogloia (Diatomeae: Bacillariophyceae): a preliminary checklist for Yap, Micronesia, with new ultrastructure images and a review of problems1
Lobban, Christopher S.
Nova Hedwigia Band 120 Heft 1-4 (2025), p. 313 - 417
121 references
published: Apr 30, 2025
published online: Jan 29, 2025
manuscript accepted: Sep 4, 2024
final revised version received: Aug 27, 2024
manuscript revision requested: Aug 27, 2024
manuscript received: Apr 4, 2024
DOI: 10.1127/nova_hedwigia/2025/0977
ArtNo. ESP050012031017, Price: 29.00 €
Abstract
As part of a broad collaborative study of Mastogloia taxonomy and biogeography, I consider 47 taxa: 45 in Yap, including four new species and 41 taxa more or less confidently identified in samples from Yap, along with specimens of those taxa from across the region. Observations from elsewhere in the region have been included where necessary to establish the ultrastructure of these species as they occur in Micronesia. Some species are well known from SEM studies, others are known only from light microscopy; many have taxonomic and/or nomenclatural questions, which are discussed but mostly not resolved within the scope of this paper. In many cases, studies in other regions and of type material will be necessary to resolve those questions. First SEM observations are presented for M. citrus, M. delicatissima, M. gomphonemoides, M. horvathiana, M. kjellmanii, M. pulchella, M. singaporensis, and M. sulcata. Special effort was made to document the partectal rings, especially advalvar faces and internal structure, if any, in suitable broken specimens, and to find “Rosetta Stone” specimens in SEM, where external and internal aspects of the cells are linked together. Mastogloia tridacnula sp. nov. is described from Yap based on its distinctive fluted outline. Formal recognition of Simonsen’s Section Marginulatae is proposed with three new species, two reported only from Guam and Chuuk: M. circumscripta sp. nov., previously identified as M. ciskeiensis, M. guamensis sp. nov., and M. pluteis sp. nov. Two taxa in the Yap flora previously reported from Guam are described in detail and reconsidered as new species: M. davisii sp. nov. is distinguished from M. adriatica var. linearis and typed with a population from Saipan, Commonwealth of the Northern Mariana Islands (CNMI) and M. witkowskii sp. nov. from M. achnanthioides. Specimens previously identified as M. cannii are reconsidered as M. delicastissima, and specimens of Mastogloia manokwariensis are reconsidered as M. pusilla var. subcapitata. Girdle bands and plastids are considered for their potential to add taxonomic characters. Two hypotheses of Mastogloia marine tropical biogeography emerge from our knowledge to date: (1) there is a single global distribution with a center of diversity in the Indomalaysian islands, as suggested by Hustedt; (2) there are two or more centers of diversity, the others being potentially the Caribbean/Gulf of Mexico and the Mediterranean. 1 This paper is dedicated to the memory of Andrzej Witkowski (1955–2023).
Keywords
biogeography • Federated States of Micronesia (FSM) • floristics • Guam • Marshall Islands • new species • nomenclature • Saipan • taxonomy