Eastern Massassauga rattlesnake in Chicago

A postal worker saw an Eastern Massassauga rattler in front of his truck. The news article implies that he stopped before hitting it and perhaps herded it off the road. The Eastern Massassauga is an endangered species, wiped out over much of its former range.

Jon Vosburg found the four-foot snake slithering in front of his truck in North Barrington.

Vosburg sent the photo to animal control. They determined it was a rare Eastern Massasauga Rattlesnake.

Vosburg says he is glad he didn’t run it over but he says he’ll look out for it from now on.

The Eastern Massassauga Rattlesnake or Sistrurus catenatus catenatus. is a subspecies of Massassauga Rattler. It occurs in Ontario from Windsor and the Niagara Peninsula north to Georgian Bay and east to the Muskoka Lakes. In the United States, it is found from central New York to Iowa and Missouri.

Images are from the Canadian Museum of Nature.

You can read about rattlesnake conservation in Michigan.

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Sensitive cat

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Have you ever wondered what it would be like to have an extension of your spine sticking out into the world.

Gekkos use their tails for balance

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In the past, we’ve often assumed that animals’ tails were mere plumes or decorations. We could see that grazing animals use theirs for fly whisks. But we weren’t clear about all the other uses for tails.

gekko in flight

Now it seems that gekkos use their tales to slow falls and to prevent them in the first place. Ed at Not Exactly Rocket Science tells us about the research into gekko tails.

They use their tails for gliding and also to keep themselves from falling when they are climbing up walls.

Moose noses

When something is under your nose, you tend to think it’s ordinary and obvious. Maybe you don’t look at it as closely as you should. For example, ever since Canada has been known to science, there has been a big, water-loving deer relative called the moose. We’ve laughed at its bulging nose, but have we looked at it? A few years ago somebody did. I remember hearing about it on the radio.

Case studies in novel narial anatomy: 2. The enigmatic nose of moose (Artiodactyla: Cervidae: Alces alces)
—Andrew B. Clifford and Lawrence M. Witmer
Abstract

The facial region of moose Alces alces is highly divergent relative to other cervids and other ruminants. In particular, the narial region forms an expanded muzzle or proboscis that overhangs the mouth. The nose of moose provides a case study in the evolution of narial novelty within a phylogenetically well-resolved group (Cervidae).

The function of the nasal apparatus of moose remains enigmatic, and new hypotheses are proposed based on our anatomical findings. Head specimens of moose and outgroup taxa were subjected to medical imaging (CT scanning), vascular injection, gross anatomical dissection, gross sectioning, and skeletonization.

Moose noses are characterized by highly enlarged nostrils accompanied by specialized musculature, expanded nasal cartilages, and an increase in the connective-tissue pad serving as the termination of the alar fold. The nostrils are widely separated, and the rhinarium that encircles both nostrils in outgroups is reduced to a tiny central patch in moose. The dorsal lateral nasal cartilage is modified to form a pulley mechanism associated with the levator muscle of the upper lip. The lateral accessory nasal cartilage is enlarged and serves as an attachment site for musculature controlling the aperture of the nostril, particularly the lateralis nasi, the apical dilatators, and the rectus nasi. Bony support for narial structures is reduced. Moose show greatly enlarged nasal cartilages, and the entire osseocartilaginous apparatus is relatively much larger than in outgroups. The nasal vestibule of moose is very large and houses a system of three recesses: one rostral and one caudal to the nostrils, and one associated with the enlarged fibrofatty alar fold. As a result of the expanded nasal vestibule, osseous support for the nasal conchae (i.e. turbinates) has retracted caudally along with the bony nasal aperture. The nasoturbinate and its mucosal counterparts (dorsal nasal concha and rectal fold) are reduced. The upturned maxilloturbinate, however, is associated with an enlarged ventral nasal concha and alar fold.

Moose are the only species of cervid with these particular characteristics, indicating that this anatomical configuration is indeed novel. Although functional hypotheses await testing, our anatomical findings and published behavioural observations suggest that the novel narial apparatus of moose probably has less to do with respiratory physiology than with functions pertaining specifically to the nostrils. The widely separated and laterally facing nostrils may enhance stereolfaction (i.e. extracting directional cues from gradients of odorant molecules in the environment), but other attributes of narial architecture (enlarged cartilages, specialized musculature, recesses, fibrofatty pads) suggest that this function may not have been the evolutionary driving force. Rather, these attributes suggest a mechanical function, namely, an elaborated nostril-closing system.
(Accepted September 18 2003)

Andrew B. Clifford and Lawrence M. Witmer (2004). Case studies in novel narial anatomy: 2. The enigmatic nose of moose (Artiodactyla: Cervidae: Alces alces). Journal of Zoology, 262, pp 339-360
doi:10.1017/S0952836903004692

It’s nice to know that there’s a name for telling the direction of a smell; but I think I need a picture to understand all the rest.

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Ventastega fills another gap in tetrapod evolution

Tiktaalik was a tetrapod with legs that was still mostly lobe-finned fish. Ventastega is a tetrapod with legs that is closer to earlier lobe-finned fish like Acathostega. Here’s a bit from the Nature News:

fossil tetrapod Ventastega curonicaFossils of a four-legged fish have filled in our understanding of the evolution of land-based vertebrates.

Initially described in 1994, early specimens of Ventastega curonica were fragmented, and hard to interpret. New examples from Latvia have now allowed researchers to reconstruct the head, shoulders and part of the pelvis of the ugly looking beast (press release, research paper in Nature).

The editor’s summary in Nature notes that the new work shows Ventastega has the skull shape of an early tetrapod but the proportions of a fish. It provides new insights in the evolution of early land-dwelling vertebrates (called tetrapods) some 370 million years ago in the Late Devonian period.

“From a distance, it would have looked like an alligator,” says study author Per Ahlberg, of Uppsala University in Sweden (BBC). “But closer up, you would have noticed a real tail fin at the back end, a gill flap at the side of the head; also lines of pores snaking across head and body. In terms of construction, it had already undergone most of the changes from fish towards land animal, but in terms of lifestyle you are still looking at an animal that is habitually aquatic.”

tetrapod vossil Ventastega

Ahlberg speculates that it was crawling around on sandy banks and eating stranded fish in tidal creeks (AP).

Ted Daeschler, paleontologist at the Academy of Natural Sciences in Philadelphia, explains to National Geographic that although we have a general outline of the transition between fish and tetrapods there’s a lot we don’t know. It’s like building a house, he says: “We’ve got the frame built. We know what the rooms are shaped like. But we haven’t put in the electricity, installed the lamps, or put Sheetrock on the walls.”

Picture upper: Philip Renne and Per Ahlberg
Picture lower: Ventastega in side view / Per Ahlberg

Here’s the abstract from Thursday’s Nature:

Nature 453, 1199-1204 (26 June 2008) | doi:10.1038/nature06991; Received 22 November 2007; Accepted 9 April 2008

Ventastega curonica and the origin of tetrapod morphology

Per E. Ahlberg1, Jennifer A. Clack2, Ervi macrns Luks caronevic carons3, Henning Blom1 & Ivars Zupincedils caron4

  1. Subdepartment of Evolutionary Organismal Biology, Department of Physiology and Developmental Biology, Uppsala University, Norbyvägen 18A, 752 36 Uppsala, Sweden
  2. University Museum of Zoology, Cambridge, Downing Street, Cambridge CB2 3EJ, UK
  3. Department of Geology, University of Latvia, Rainis Blvd 19, Riga LV-1586, Latvia
  4. Natural History Museum of Latvia, K. Barona Str. 4, Riga LV-1712, Latvia

Correspondence to: Per E. Ahlberg1 Correspondence and requests for materials should be addressed to P.E.A. (Email: per.ahlberg@ebc.uu.se).

The gap in our understanding of the evolutionary transition from fish to tetrapod is beginning to close thanks to the discovery of new intermediate forms such as Tiktaalik roseae. Here we narrow it further by presenting the skull, exceptionally preserved braincase, shoulder girdle and partial pelvis of Ventastega curonica from the Late Devonian of Latvia, a transitional intermediate form between the ‘elpistostegids’ Panderichthys and Tiktaalik and the Devonian tetrapods (limbed vertebrates) Acanthostega and Ichthyostega. Ventastega is the most primitive Devonian tetrapod represented by extensive remains, and casts light on a part of the phylogeny otherwise only represented by fragmentary taxa: it illuminates the origin of principal tetrapod structures and the extent of morphological diversity among the transitional forms.

The Fish Directory

I just happened across this beautiful blog, which is attempting to catalog fish of all descriptions.

smooth trunkfish from Honduras

Speckled trunkfish from Honduras

Visit the Fish Directory.

Xenoposeidon, another skeleton in the closet

Sauropod Vertebra of the Week: get a look at this beauty: Xenoposeidon proneukos, a new English dinosaur. The XenoposeIdon vertebra is shown here:

xenopoiseidon vertebra fragment

This partial vertebra was collected in the 1890s and stored away in the London Museum of Natural History until recently, when palaeontologist Mike Taylor discovered that it was unusual. He asked Darren Naish of Tetrapod Zoology about it, and Darren had a partially written review article, so they decided to collaborate on a new description. The bone turned out to belong to a very large, unknown dinosaur which was different enough to be placed in its own genus. There’s a whole week of posts about it in the link, plus another link to a web-friendly page with lots of detailed images and a simple connecting narrative. Enjoy!

This reminds me of the Barosaurus found by the Royal Ontario Museum last year in its own closet:

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