Sánchez-García Alba, Nel André, Arillo Antonio, Solórzano Kraemer Mónica M
Departament de Dinàmica de la Terra i de l'Oceà and Institut de Recerca de la Biodiversitat (IRBio), Facultat de Ciències de la Terra, Universitat de Barcelona, Barcelona, Spain.
Institut de Systématique, Évolution, Biodiversité, Museum national d'Histoire naturelle, Paris, France.
PeerJ. 2017 Sep 5;5:e3760. doi: 10.7717/peerj.3760. eCollection 2017.
Pondweed bugs (Hemiptera: Mesoveliidae), considered a sister group to all other Gerromorpha, are exceedingly rare as fossils. Therefore, each new discovery of a fossil mesoveliid is of high interest, giving new insight into their early evolutionary history and diversity and enabling the testing of their proposed relationships. Here, we report the discovery of new mesoveliid material from Spanish Lower Cretaceous (Albian) amber, which is the first such find in Spanish amber. To date, fossil records of this family only include one species from French Kimmeridgian as compression fossils, two species in French amber (Albian-Cenomanian boundary), and one in Dominican amber (Miocene). The discovery of two males and one female described and figured as Sánchez-García & Solórzano Kraemer gen. et sp. n., and a single female described and figured as Sánchez-García & Nel, gen. et sp. n., reveals novel combinations of traits related to some genera currently in the subfamily Mesoveliinae. Brief comments about challenges facing the study of fossil mesoveliids are provided, showing the necessity for a revision of the existing phylogenetic hypotheses. Some of the specimens were studied using infrared microscopy, a promising alternative to the systematic study of organisms preserved in amber that cannot be clearly visualised. The new taxa significantly expand the fossil record of the family and shed new light on its palaeoecology. The fossils indicate that Mesoveliidae were certainly diverse by the Cretaceous and that numerous tiny cryptic species living in humid terrestrial to marginal aquatic habitats remain to be discovered. Furthermore, the finding of several specimens as syninclusions suggests aggregative behaviour, thereby representing the earliest documented evidence of such ethology.
小眼水黾科昆虫（半翅目：小眼水黾科）被认为是所有其他黾蝽类昆虫的姐妹群，作为化石极其罕见。因此，每一次小眼水黾科化石的新发现都备受关注，能为它们的早期进化历史和多样性提供新见解，并有助于检验它们所提出的亲缘关系。在此，我们报告从西班牙下白垩统（阿尔必阶）琥珀中发现的新小眼水黾科材料，这是在西班牙琥珀中的首次此类发现。迄今为止，该科的化石记录仅包括来自法国基默里吉阶的一个作为压型化石的物种、法国琥珀（阿尔必阶 - 森诺曼阶边界）中的两个物种以及多米尼加琥珀（中新世）中的一个物种。两个雄性和一个雌性被描述并绘制成 Sánchez - García & Solórzano Kraemer 新属新种，还有一个雌性被描述并绘制成 Sánchez - García & Nel 新属新种，揭示了与当前小眼水黾亚科某些属相关的性状新组合。文中还对小眼水黾科化石研究面临的挑战进行了简要评论，表明有必要修订现有的系统发育假说。部分标本使用红外显微镜进行了研究，这是对保存在琥珀中无法清晰观察的生物体进行系统研究的一种有前景的替代方法。这些新分类单元显著扩展了该科的化石记录，并为其古生态学提供了新线索。这些化石表明，小眼水黾科在白垩纪时肯定已经多样化，并且仍有许多生活在潮湿陆地至边缘水生栖息地的微小隐秘物种有待发现。此外，多个标本作为共生内含物被发现，表明存在聚集行为，从而代表了这种行为学最早的文献记载证据。
