scholarly journals The evolution of scale sensilla in the transition from land to sea in elapid snakes

Open Biology ◽  
2016 ◽  
Vol 6 (6) ◽  
pp. 160054 ◽  
Author(s):  
Jenna M. Crowe-Riddell ◽  
Edward P. Snelling ◽  
Amy P. Watson ◽  
Anton Kyuseop Suh ◽  
Julian C. Partridge ◽  
...  

Scale sensilla are small tactile mechanosensory organs located on the head scales of many squamate reptiles (lizards and snakes). In sea snakes and sea kraits (Elapidae: Hydrophiinae), these scale organs are presumptive scale sensilla that purportedly function as both tactile mechanoreceptors and potentially as hydrodynamic receptors capable of sensing the displacement of water. We combined scanning electron microscopy, silicone casting of the skin and quadrate sampling with a phylogenetic analysis to assess morphological variation in sensilla on the postocular head scale(s) across four terrestrial, 13 fully aquatic and two semi-aquatic species of elapids. Substantial variation exists in the overall coverage of sensilla (0.8–6.5%) among the species sampled and is broadly overlapping in aquatic and terrestrial lineages. However, two observations suggest a divergent, possibly hydrodynamic sensory role of sensilla in sea snake and sea krait species. First, scale sensilla are more protruding (dome-shaped) in aquatic species than in their terrestrial counterparts. Second, exceptionally high overall coverage of sensilla is found only in the fully aquatic sea snakes, and this attribute appears to have evolved multiple times within this group. Our quantification of coverage as a proxy for relative ‘sensitivity’ represents the first analysis of the evolution of sensilla in the transition from terrestrial to marine habitats. However, evidence from physiological and behavioural studies is needed to confirm the functional role of scale sensilla in sea snakes and sea kraits.

2006 ◽  
Vol 84 (3) ◽  
pp. 490-494 ◽  
Author(s):  
Roberto Romani ◽  
Donato Antonio Grasso ◽  
Alessandra Mori ◽  
Nunzio Isidoro ◽  
Francesco Le Moli

The fine morphology of glandular structures associated with the antennae is reported for the first time in a social parasite ant, the obligate slave-maker Polyergus rufescens (Latreille, 1798). In this species, external pores have been detected through scanning electron microscopy only on the scape of the female castes (queen and worker). Each pore is associated internally with a bicellular secretory unit by means of a cuticular duct. The number of secretory cells appears to be higher in queens than in workers. Similar exocrine structures have been found also in workers of Formica cunicularia Latreille, 1798, a common host species of P. rufescens. The possible functional role of this gland is discussed.


Author(s):  
Douglas William Jones

Within the past 20 years, archaeobotanical research in the Eastern United States has documented an early agricultural complex before the dominance of the Mesoamerican domesticates (corn, beans, and squash) in late prehistoric and historic agricultural systems. This early agricultural complex consisted of domesticated plants such as Iva annua var.macrocarpa (Sumpweed or Marshelder), Hellanthus annuus (Sunflower) and Chenopodium berlandieri, (Goosefoot or Lasbsquarters), and heavily utilized plants such as Polygonum erectum (Erect Knotweed), Phalaris caroliniana (May grass), and Hordeum pusillum (Little Barley).Recent research involving the use of Scanning Electron Microscopy (SEM) specifically on Chenopodium has established diagnostic traits of wild and domesticated species seeds. This is important because carbonized or uncarbonized seeds are the most commonly recovered Chenopodium material from archaeological sites. The diagnostic seed traits assist archaeobotanists in identification of Chenopodium remains and provide a basis for evaluation of Chenopodium utilization in a culture's subsistence patterns. With the aid of SEM, an analysis of Chenopodium remains from three Late Prehistoric sites in Northwest Iowa (Blood Run [Oneota culture], Brewster [Mill Creek culture], and Chan-Ya-Ta [Mill Creek culture]) has been conducted to: 1) attempt seed identification to a species level, 2) evaluate the traits of the seeds for classification as either wild or domesticated, and 3) evaluate the role of Chenopodium utilization in both the Oneota and Mill Creek cultures.


2009 ◽  
Vol 221 (03) ◽  
Author(s):  
B Steiger ◽  
I Leuschner ◽  
D Denkhaus ◽  
D von Schweinitz ◽  
T Pietsch
Keyword(s):  

2020 ◽  
Vol 9 (2) ◽  
pp. 78-88
Author(s):  
Mulugeta Mulat ◽  
Raksha Anand ◽  
Fazlurrahman Khan

The diversity of indole concerning its production and functional role has increased in both prokaryotic and eukaryotic systems. The bacterial species produce indole and use it as a signaling molecule at interspecies, intraspecies, and even at an interkingdom level for controlling the capability of drug resistance, level of virulence, and biofilm formation. Numerous indole derivatives have been found to play an important role in the different systems and are reported to occur in various bacteria, plants, human, and plant pathogens. Indole and its derivatives have been recognized for a defensive role against pests and insects in the plant kingdom. These indole derivatives are produced as a result of the breakdown of glucosinolate products at the time of insect attack or physical damages. Apart from the defensive role of these products, in plants, they also exhibit several other secondary responses that may contribute directly or indirectly to the growth and development. The present review summarized recent signs of progress on the functional properties of indole and its derivatives in different plant systems. The molecular mechanism involved in the defensive role played by indole as well as its’ derivative in the plants has also been explained. Furthermore, the perspectives of indole and its derivatives (natural or synthetic) in understanding the involvement of these compounds in diverse plants have also been discussed.


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