貽貝蝦（介形類）是小型的、雙殼類甲殼動(dòng)物,，生活在海洋和淡水環(huán)境中,。
據(jù)6月19日的《科學(xué)》雜志報(bào)道說，介形類動(dòng)物（是遠(yuǎn)古的一種節(jié)肢動(dòng)物）的巨大精子常常比它們自己的身體長(zhǎng)度還要長(zhǎng),。這些動(dòng)物可回溯到至少1億年以前,。用巨大的精子來性交是一種在整個(gè)動(dòng)物王國(guó)中散布的某些不同組群動(dòng)物的一種策略。這一發(fā)現(xiàn)表明,，盡管在產(chǎn)生這種巨型精子上可能會(huì)受到某些進(jìn)化上的約束,，但對(duì)這些節(jié)肢動(dòng)物來說，這仍然是一種可取的方式,。
在一篇Brevium 中,，Renate Matzke-Karasz及其同僚介紹了他們是如何用一個(gè)罕見的保留下來的軟組織樣本以及一種叫做“全息斷層成像術(shù)”新的成像技術(shù)來研究一種已經(jīng)絕種的介形動(dòng)物的生殖器官，并將它們與那些仍然存活在世的介形動(dòng)物進(jìn)行了比較,。 有關(guān)巨型精子在有性生殖中的研究主要是在果蠅中進(jìn)行的,，但這一新的發(fā)現(xiàn)證明了這種特征在時(shí)間跨度巨大的地質(zhì)時(shí)代中一直持續(xù)著。 這篇文章還重點(diǎn)介紹了：通過保留下的微型化石,，人們可應(yīng)用全息斷層成像術(shù)來作為一種復(fù)原過去數(shù)據(jù)的手段,。（生物谷Bioon.com）
生物谷推薦原始出處：
Science 19 June 2009:DOI: 10.1126/science.1173898
Sexual Intercourse Involving Giant Sperm in Cretaceous Ostracode
R. Matzke-Karasz,1,* R. J. Smith,2 R. Symonova,3 C. G. Miller,4 P. Tafforeau5
Reproduction with giant sperm occurs in distinct groups scattered over the animal kingdom. Although experiments in Drosophila assessed the influence of different selection pressures on this character, no information was available on its long-term stability. Sub-micrometer-resolution synchrotron quantitative phase tomography (holotomography) of exceptionally well-preserved three-dimensional Cretaceous ostracode fossils from the Brazilian Santana Formation indicates that ostracode reproduction with giant sperm persisted for at least over the past 100 million years. Remnants of the male sperm pumps as well as giant, inflated female sperm receptacles evidence that, despite high costs, reproduction with giant sperm can be an evolutionary successful strategy.
1 Department of Environmental and Geosciences, Palaeontology, and GeoBioCenter, Ludwig Maximilians University (LMU), 80333 Muenchen, Germany.
2 Lake Biwa Museum, Kusatsu, Shiga 525-0001, Japan.
3 Department of Zoology, Charles University, 12844 Prague, Czech Republic.
4 Department of Palaeontology, Natural History Museum, London SW7 5BD, UK.
5 European Synchrotron Radiation Facility (ESRF), 38043 Grenoble, France.
