Complete

Meruidae Spangler and Steiner 2005

Meru phyllisae Spangler and Steiner 2005

Warren Steiner, Alex Wild, and Andrew Short
Click on an image to view larger version & data in a new window
Click on an image to view larger version & data in a new window
Containing group: Adephaga

Introduction

Meru phyllisae is among the world's smallest and rarest beetles. Less than a millimeter in length, M. phyllisae is known only from the El Tobogán de la Selva cascade in Amazonian Venezuela. There, specimens have been collected clinging to vegetative debris submerged in the stream.

As in other crawling aquatic Adephaga, Meru has a hydrodynamic teardrop shape. The feeding habits of Meru are not known, but lab observations and mouthpart morphology suggest that it may graze on algal filaments or fungal hyphae (Spangler & Steiner 2005). Intriguingly, the population at El Tobogán is dimorphic in wing morphology. Most individuals are brachypterous and flightless but a few have fully developed flight wings, suggesting adaptation to temporary pools or flooding.

The single species is placed in its own family, Meruidae, in the suborder Adephaga. Meruidae is among the newest beetle families, discovered in the 1980s and formally described in 2005 (Spangler & Steiner 2005).

Characteristics

The following diagnosis for the adults is modified from Spangler & Steiner (2005):

  1. Size small, total length less than 1 millimeter.
  2. Body sculpture rough, and integument covered with flat, wrinkled setae.
  3. Tarsal claws pectinate.
    Click on an image to view larger version & data in a new window
    Click on an image to view larger version & data in a new window

    Meru phyllisae tibiae and tarsi. ©

  4. Tibial spurs tridentate (inner metatibial spur serrate).
  5. Labrum with pairs of overlapping spatulate setae.
  6. Legs without swimming hairs.
  7. Scapus small and rounded.
  8. Antennal flagellum with segments alternately large and small.
Click on an image to view larger version & data in a new window
Click on an image to view larger version & data in a new window

Meru phyllisae antennal flagellum. ©

In spite of efforts to rear Meru in the laboratory (Spangler & Steiner 2005), immature forms are unknown.

Discussion of Phylogenetic Relationships

The small size and corresponding reduction of morphological characters complicates the placement of Meru within Adephaga. Nonetheless, the first morphological (Beutel et al 2006) and molecular (Balke et al 2008) phylogenies both infer a sister relationship between Meru and Noteridae, the burrowing water beetles.

Other Names for Meru phyllisae Spangler and Steiner 2005

References

Balke, M., I. Ribera, R. Beutel, A. Viloria, M. Garcia, and A.P. Vogler. 2008. Systematic placement of the recently discovered beetle family Meruidae (Coleoptera: Dytiscoidea) based on molecular data. Zoologica Scripta, 37: 647-650. doi: 10.1111/j.1463-6409.2008.00345.x

Beutel, R.G., M. Balke, and W.E. Steiner. 2006. The systematic position of Meruidae (Coleoptera, Adephaga) and the phylogeny of the smaller aquatic adephagan beetle families. Cladistics, 22: 102-131. doi:10.1111/j.1096-0031.2006.00092.x

Spangler, P.J. and W.E. Steiner. 2005. A new aquatic beetle family, Meruidae, from Venezuela (Coleoptera: Adephaga). Systematic Entomology, 29: 339-357.

Information on the Internet

Title Illustrations
Click on an image to view larger version & data in a new window
Click on an image to view larger version & data in a new window
Scientific Name Meru phyllisae
Specimen Condition Dead Specimen
Identified By Warren Steiner
Life Cycle Stage Adult
View lateral
Copyright ©
About This Page


Smithsonian National Museum of Natural History, Washington, D. C., USA

Alex Wild
University of Illinois, Urbana, Illinois, USA


Correspondence regarding this page should be directed to Warren Steiner at , Alex Wild at , and Andrew Short at

All Rights Reserved.

Citing this page:

Steiner, Warren, Alex Wild, and Andrew Short. 2010. Meruidae Spangler and Steiner 2005. Meru phyllisae Spangler and Steiner 2005. Version 17 August 2010. http://tolweb.org/Meru_phyllisae/29297/2010.08.17 in The Tree of Life Web Project, http://tolweb.org/

edit this page
close box

This page is a Tree of Life Leaf Page.

Each ToL leaf page provides a synopsis of the characteristics of a group of organisms representing a leaf at the tip of the Tree of Life. The major distinction between a leaf and a branch of the Tree of Life is that a leaf cannot generally be further subdivided into subgroups representing distinct genetic lineages.

For a more detailed explanation of the different ToL page types, have a look at the Structure of the Tree of Life page.

close box

Meru phyllisae

Page Content

articles & notes

collections

people

Explore Other Groups

random page

  go to the Tree of Life home page
top