Vol. 59, 2020

(update: 2020.07.06; 08.05)

Special Issue: Fossil and Modern Clam Shrimp (Branchiopoda: Spinicaudata, Laevicaudata)

Developmental and Functional Morphology of Eulimnadia braueriana Ishikawa, 1895 (Branchiopoda: Spinicaudata) Feeding Structures: Combination of Filtering and Scraping Feeding Mechanisms

Jer-Yuh Liu¹, Chun-Chieh Wang^2,*, and D. Christopher Rogers³

¹Environmental Science Technology Consultants Corporation, 8F, No. 280, Sec. 4, Zhonxiao E. Rd., Taipei 10617, Taiwan. E-mail: jeryuhliu@gmail.com (Liu)
²Guangxi Key Laboratory of Marine Environmental Science, Guangxi Beibu Gulf Marine Research Center, Guangxi Academy of Sciences, 98 Dalin Road, Nanning, Guangxi 530007, China. *Correspondence: E-mail: webberpy@gmail.com (Wang)
³Kansas Biological Survey, and The Biodiversity Institute, The University of Kansas, Higuchi Hall, 2101 Constant Avenue, Lawrence, KS 66047-3759, USA. E-mail: Branchiopod@gmail.com (Rogers)

(Received 7 August 2020 / Accepted 20 February 2020)
Special issue (articles 32-46) communicated by Thomas A. Hegna and D. Christopher Rogers

Large branchiopods inhabit diverse continental habitats worldwide. Their feeding ecology, nevertheless, remains largely unknown. The few functional morphology studies that have been conducted have mostly focused on adults or larvae, seldom have the two been compared collectively. In this study, we examined the feeding structures in Eulimnadia braueriana Ishikawa, 1895 from nauplius to adult to clarify their feeding mechanisms and then compared them with the other two sympatric branchiopods (Branchinella kugenumaensis and Lynceus biformis) in Siangtian Pond, Taiwan. Naupliar second antennae and mandibles are similar to those of other species, suggesting filter-feeding. The naupliar feeding structures, including the mandibular palp and naupliar process, gradually degenerate during the juvenile stage. Simultaneously, the molar surface, maxillae, and second antennae continue developing, reaching their adult form in later juvenile substages. The molar surface and thoracopod setal morphology are similar to those of other filter-feeding branchiopods, but adults also have scraping setae on the first several thoracopod pairs. Nearly all naupliar primary feeding structures change through development, particularly during the early juvenile substages, whereas late juvenile substages and adult morphology are similar. Eulimnadia braueriana transforms from pelagic filtering nauplii to adults that combine benthic filtering and scraping. Comparisons of molar and thoracopod morphology between coexisting branchiopod species show some similarities and differences in filtering and scraping feeding structures, implying potential foraging resource differentiation among species.

Key words: Branchinella kugenumaensis, Lynceus biformis, Mandible, Second antenna, Thoracopod.

Citation: Liu JY, Wang CC, Rogers DC. 2020. Developmental and functional morphology of Eulimnadia braueriana Ishikawa, 1895 (Branchiopoda: Spinicaudata) feeding structures: combination of filtering and scraping feeding mechanisms. Zool Stud 59:35. doi:10.6620/ZS.2020.59-35.