Dominican Amber Spiders info.pdf - TerraTreasures

27 Pages·2008·2.58 MB·English

Forthcoming title due to be
published May 2008
D
ominican
a S
mber piDerS
A comparative palaeontological-
neontological approach to identification,
faunistics, ecology and biogeography
Dr David Penney
Siri Scientific Press
Special Offer on
pre-publication orders!
(until 15th April 2008)
Please see below for further details and sample pages
Book details and ordering information
Title: Dominican Amber Spiders
Subtitle: A comparative palaeontological–neontological approach to
identification, faunistics, ecology and biogeography
Author: David Penney
Publisher: Siri Scientific Press
ISBN: Forthcoming
Publication date: Expected May 2008
Dimensions: 245 by 170 mm
Cover: Soft (300 gsm, gloss laminated)
Number of pages: 178 (130 gsm silk coated paper)
Number of illustrations: 300+ including high quality colour photos
Summary: see attached sample pages
Price: £40.00 (postage, packaging & handling extra, but free for pre-
publication orders*)
Methods of payment
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sterling) to David Penney and send to: Dr David Penney, 50 Burnside
Drive, Burnage, Manchester, M19 2LZ, United Kingdom
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A comparative palaeontological-
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The author is a Visiting Research Fellow at the University of Manchester, A identification, faunistics, ecology
UK and the leading world expert on fossil spiders preserved in amber and m
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in which they lived. In this book Dr Penney provides a comprehensive
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synopsis of what is known about the Dominican Republic amber spider p
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fauna, much of which is based on his numerous scientific publications in d
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leading international journals. However, the book is not intended solely for r
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academics. It contains more than 300 illustrations including many colour

photographs, which should permit the identification of both the fossil and living

Hispaniolan spider fauna by both amber collectors and spider enthusiasts.

The introductory chapters provide full coverage of what is known about the

geological origins, chemistry and botanical source of Dominican amber and
the mining, preparation and distribution processes. which the author has
witnessed first hand. Previously unpublished data on historical biogeography S
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should make this book of interest to all those interested in the biogeography r
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of the Caribbean region. The volume also contains an extensive bibliography
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of almost 350 entries providing a valuable resource for anybody interested in i
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fossil resins. This book far surpasses anything else availabe on this subject
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and is expected to remain the leading reference work for many years to come. fi
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Dr David Penney
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Foreword
It is not possible to fully appreciate the origins, evolutionary history or present biodiversity of any group
of organisms until one considers the fossil record. Yet despite this obvious statement, there often remains
a palpable void between the disciplines of palaeontology and neontology, and scientists from both camps
are to blame. More often than not, neontologists will not even consider fossils in systematic studies or when
describing new taxa. However, this is not a universal phenomenon and I am encouraged by the increasing
number of neontologists who do consider fossils. In some cases they may be unaware that fossils exist, but given
the electronic bibliographic databases that are currently available this is not really a credible excuse. Others
argue that fossils do not preserve sufficient detail for comparative studies with recent specimens. However,
as you will see in this volume, recent applications of high-resolution imaging technology to palaeontological
specimens render this argument one of semantics or methodology. Some neontologists have told me they do
not consider fossils in their studies because they are unimportant and they remain steadfast in this respect
despite my repeated attempts to convince them otherwise. A perfect example of just how important it is
to consider fossils relates to the spider family Archaeidae, which was first described in 1854 from fossils
preserved in Baltic amber, prior to being found in the extant fauna three decades later. Not only are fossils of
this family important from a taxonomic and nomenclatorial perspective, but fossils can also shed much light
on the historical biogeography of this family. The extant fauna is restricted to South Africa and Madagascar,
whereas fossils are known from the Baltic region, France, Myanmar, China and Kazakhstan.
Many palaeontologists are accidental zoologists. For some, having graduated from an Earth Sciences
degree course, most of their academic background lies in the physical, rather than biological sciences. Many
are unfamiliar with the finer details of taxonomic practices for extant members of the groups they then choose
to go on and study. There are many examples in the literature of new fossil taxa that have been erected solely on
the basis of age. In many cases, there is no indication that comparative extant specimens have been examined,
the diagnoses are often based on features not considered reliable for extant species, nor do the diagnoses serve
to differentiate the fossil taxa from living forms. Given that many groups of organisms demonstrate a high
degree of evolutionary stasis, such an approach is inappropriate. Using such an approach makes comparisons
of neontological and palaeontological faunistic datasets (e.g., in order to assess any degree of change over
time) impossible or highly misleading. As a zoologist turned palaeontologist I sit in both camps and suppose
I am an accidental geologist. I also have a lot of catching up to do! Ultimately however, researchers from
both these (and other) disciplines need to enter into each others’ realms in order to address effectively the
increasingly complex macro-scale evolutionary and biological questions that we currently pose in order to
secure research funding to understand the history of life on Earth.
This book has four main purposes. Firstly, to demonstrate a perfect example of how fossil and
extant faunas can be extremely similar and thus warrant a combined neontologicial and palaeontological
taxonomic approach. Secondly, to show how comparisons of faunas based on such an approach can permit
qualitative and quantitative investigations of interesting palaeo/biological questions, for example, relating to
palaeoecology and historical biogeography. Thirdly, to provide comprehensive information on our current
knowledge regarding the origins and formation of Hispaniola and Dominican Republic amber, including
methods for preparation and study. Finally, the book serves as an introduction to the fossil record of spiders,
and specifically, the identification of spiders preserved as fossils in Dominican Republic amber (and also
from the extant Hispaniolan fauna). It is not intended as an exhaustive guide for species identification, but
should permit the reader to identify their specimen at least to family, and in some cases even further. Readers
will then be directed to the relevant literature required to take their identifications to species level. Thus, this
volume is aimed at a broad audience and some will have a better knowledge of the subject than others. Rather
than include a comprehensive glossary, I have attempted to limit technical terms and explain them where they
appear in the text.
Finally, it is easy to start an endeavour such as this, and indeed it was a labour of love. However, it
is not so easy to know when to stop. New fossil and extant species are being discovered and described all

Contents
1. Introduction................................................................................................................................................10
Caught in the act...................................................................................................................................11
What are spiders and how do they fit into the grand scheme of things?..............................................13
Spiders in the fossil record...................................................................................................................15
Age, radiations and extinction events...................................................................................................1
What is the importance of fossil spiders and why should we study them?..........................................19
2. Dominican Republic amber.......................................................................................................................21
Some history.........................................................................................................................................22
A note on terminology..........................................................................................................................23
Botanical source and age of Dominican amber....................................................................................23
The amber producing tree........................................................................................................23
Age of Dominican amber.........................................................................................................25
Physical and chemical properties.........................................................................................................26
Tissue and DNA preservation..............................................................................................................27
Authenticity (distinguishing amber from copal and fakes).................................................................28
The mining process..............................................................................................................................28
The amber mines......................................................................................................................29
The extraction process.............................................................................................................29
From mine to museum..............................................................................................................30
Methods of preparation and study........................................................................................................31
Preparation of raw amber inclusions......................................................................................31
Further preparation for closer scrutiny of inclusions..............................................................33
Light microscopy and photography.........................................................................................34
Advanced microscopy and computed tomography..................................................................35
Major collections of Dominican amber................................................................................................37
Conservation and curation of amber collections..................................................................................37
The diversity of Dominican amber inclusions.....................................................................................38
3. History of Hispaniolan araneology...........................................................................................................40
The extant fauna..................................................................................................................................40
The fossil fauna....................................................................................................................................41
Systematic checklist of fossil and extant Hispaniolan spiders............................................................42
4. Key to Hispaniolan spider families (fossil & extant)..............................................................................48
Morphology and terminology..............................................................................................................48
Key to the spider families of Hispaniola.............................................................................................52
Highly distinctive morphological features...............................................................................52
Dichotomous key to all Hispaniolan spider families...............................................................55
5. Family descriptions....................................................................................................................................65
Dipluridae.........................................................................................................................................................66
Cyrtaucheniidae................................................................................................................................................67
Microstigmatidae..............................................................................................................................................67
Barychelidae.....................................................................................................................................................68
Theraphosidae..................................................................................................................................................69
Filistatidae........................................................................................................................................................70
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Sicariidae..........................................................................................................................................................1
Scytodidae........................................................................................................................................................2
Drymusidae......................................................................................................................................................73
Ochyroceratidae...................................................................................................................................73
Pholcidae..........................................................................................................................................................75
Caponiidae........................................................................................................................................................
Tetrablemmidae................................................................................................................................................78
Segestriidae......................................................................................................................................................78
Oonopidae........................................................................................................................................................79
Palpimanidae....................................................................................................................................................81
Mimetidae.........................................................................................................................................................81
Oecobiidae........................................................................................................................................................83
Hersiliidae........................................................................................................................................................84
Deinopidae.......................................................................................................................................................86
Uloboridae........................................................................................................................................................87
Nesticidae.........................................................................................................................................................89
Theridiidae.......................................................................................................................................................90
Theridiosomatidae............................................................................................................................................94
Symphytognathidae..........................................................................................................................................95
Anapidae...........................................................................................................................................................96
Mysmenidae.....................................................................................................................................................96
Linyphiidae.......................................................................................................................................................97
Nephilidae........................................................................................................................................................99
Tetragnathidae................................................................................................................................................101
Araneidae.......................................................................................................................................................102
Lycosidae.......................................................................................................................................................106
Pisauridae...........................................................................................................................................10
Oxyopidae......................................................................................................................................................108
Zoridae...........................................................................................................................................................108
Ctenidae..........................................................................................................................................................109
Desidae...........................................................................................................................................................110
Dictynidae......................................................................................................................................................111
Amaurobiidae.................................................................................................................................................112
Miturgidae......................................................................................................................................................113
Anyphaenidae.................................................................................................................................................114
Liocranidae.....................................................................................................................................................116
Clubionidae....................................................................................................................................................116
Corinnidae......................................................................................................................................................11
Trochanteriidae...............................................................................................................................................119
Prodidomidae.................................................................................................................................................120
Gnaphosidae...................................................................................................................................................120
Selenopidae....................................................................................................................................................122
Sparassidae.....................................................................................................................................................122
Philodromidae................................................................................................................................................124
Thomisidae.....................................................................................................................................................124
Salticidae........................................................................................................................................................125
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6. Aspects of palaeoecology & historical biogeography............................................................................129
The Miocene Dominican amber forest..............................................................................................130
Resin as a trap: taphonomy and bias of amber spider inclusions......................................................130
The site of resin secretion.......................................................................................................130
The entrapment process..........................................................................................................131
Do different ambers trap organisms in the same way?.........................................................133
Bias in the amber fauna..........................................................................................................135
Comparison of the fossil and extant spider faunas............................................................................137
Origins of the Hispaniolan spider fauna............................................................................................142
Predictions for the extant fauna based on the fossil fauna................................................................150
7. other fossil arachnids in Dominican amber.........................................................................................152
References cited............................................................................................................................................156
Index.............................................................................................................................................................11
10
Introduction
When most people hear the word ‘fossil’ they tend to conjure up images of giant dinosaurs such as Tyrannosaurus
rex or shelled marine molluscs. Prior to the Hollywood blockbuster movie Jurassic Park, which was based on
recreating dinosaurs through extracting their DNA from blood in the guts of fossil mosquitoes preserved in
amber, few people would entertain the notion that insects occur in the fossil record. However, insects, spiders
and other terrestrial arthropods are common as fossils (Grimaldi & Engel, 2005) and particularly so in amber,
where they are often preserved with life-like fidelity.
Amber has properties similar to amorphous, polymeric glass and is the fossilized form of tree resin,
which consists of a complex mixture of terpenoid and/or phenolic compounds. It is derived from numerous
different tree families (e.g., Pinaceae, Araucariaceae, Cupressaceae, Leguminoseae, Combretaceae to name
but a few), most of which can be determined by comparing the infrared spectra of the amber with those of
resins from extant tree species. Such techniques also serve to differentiate one amber type from another. For
example, Baltic amber has a highly characteristic plateau off one side of one of the spectrograph peaks, which
is referred to as the ‘Baltic shoulder’.
The oldest ambers that contain fossil arthropods are from the Lower Cretaceous of Lebanon (Poinar
& Milki, 2001) and Jordan (Kaddumi, 2005), although there is no reason not to expect future discoveries of
inclusions in older (e.g., Jurassic) fossil resins. Various deposits from around the world (Figure 1.1) fill in
the gaps from the Cretaceous until the present, although hardened resins younger than 40,000 years of age
are considered to be sub-fossil and are called copal (not shown in Figure 1.1). Amber is a prime example of
a Konservat-Lagerstätte (an occurrence of exceptional preservation, which permits detailed morphological
comparisons with living relatives) and so in contrast to most fossils preserved in sediments, amber inclusions
are particularly important from a phylogenetic perspective and can be used to investigate micro- as well as
macro-evolutionary processes.
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1.1 Amber deposits of the world. Data primarily from Martínez-Delclòs et al., 2004) with updates
Caught in the act
Syninclusions (two or more inclusions in the same piece of amber) often preserve interactions between
organisms, for example, behaviours such as mating (Figure 1.2), mate guarding, commensalism, parasitism
(e.g., nematode worms exiting their arthropod host, hymenopteran larvae and mites preserved in situ, still
penetrating the cuticle of their host organism), disease (e.g., pathogenic fungi), defecation, egg laying, phoresy
(one organism being transported by another—pseudoscorpions are sometimes found attached to the legs of
insects), predation and maternal care (e.g., ants carrying larvae and pupae). Even delicate spider webs are
occasionally preserved, sometimes with prey attached (Figure 1.3). So excellent is the degree of preservation
in amber that even the tiny glue droplets of spider viscid silk are often clearly visible (Figure 1.4), even
in Cretaceous ambers dating back to in excess of 100 million years (Zschokke, 2003, 2004). Amber may
also preserve the death throes of the entombed arthropods as they struggled to escape the sticky exudates,
for example, in the form of wing movements and disarticulation of body parts. Fossilized spider blood was
reported recently, exuding from joints where the resin had caused the legs to autospasize (detach as a result of
an external force) from the body (Penney, 2005a; Figure 1.5).
Such observations as those listed above are rarely, if ever, encountered in the non-amber fossil record
because of the different taphonomic processes (what happens to the organism between death and becoming
a fossil) that control the preservation of organisms in carbonate rocks and amber (Martínez-Delclòs et al.,
2004). However, I do not wish to imply here that the non-amber fossil record is any less important. An
additional consequence of this variation is that, on the whole, sediments and amber preserve different subsets
of the arthropod community. Thus, the fossil record of amber is biased towards preserving certain groups,
as are all other fossil deposits. In addition, the fossil record in general is notoriously incomplete, but not
27
exuded, the volatile components of the resin, such as sesquiterpene hydrocarbons which function to control
viscosity and flexibility, are gradually lost to produce hardened resin. In general, the processes involved in
fossilization seem to be progressive oxidation and polymerization via free-radical mechanisms. In contrast to
Baltic amber, Dominican amber does not contain succinic acid. Thus, the new species name Staphylococcus
succinus erected by Lambert et al. (1998) for a newly discovered species of bacterium in Dominican amber is
slightly inappropriate.
Tissue and DNA preservation
The mode of tissue preservation in amber appears to be a rapid and thorough fixation and dehydration, which
may be sufficient for preserving deoxyribonucleic acid (DNA) more consistently than any other kind of
fossilization process (Grimaldi et al., 1994a). Henwood (1992) reported excellent preservation of soft tissues,
including locomotory, digestive, respiratory, nervous and sensory tissues from cantharid and nitulid beetles
preserved in Dominican Republic amber. However, not all ambers preserve internal tissues in such detail.
For example, the recently discovered amber from western Amazonia appears to preserve only the cuticular
exoskeleton of the arthropod inclusions (Antoine et al., 2006).
During the early 1990s numerous researchers claimed that they had managed to extract small strings
of DNA from Dominican amber inclusions, such as the stingless bee Propblebeia dominicana (Cano et al.,
1992), a termite Mastotermes electrodominicus (DeSalle et al., 1992, 1993), a wood gnat Valeseguya disjuncta
(DeSalle, 1994) and the amber producing tree itself (Poinar et al., 1993). Even more impressive were claims
by Cano et al. (1993) of DNA extraction from a beetle Libanorhinus succinus in Lebanese amber, dating back
as far as 135 million years. A number of publications rode the crest of the amber DNA wave (e.g., Poinar,
1994), including a whole book by Poinar & Poinar (1994), which is a very pleasant read and particularly useful
for those intending to visit amber producing areas.
However, an excellent study by Austin et al. (1997) at the Natural History Museum, London, which
employed a rigorous experimental method with appropriate control groups, was unable to replicate the above-
mentioned studies. DNA was retrieved (including from the control samples, which should not have contained
any!) but all sequences detected were derived from obvious non-insect contaminants, such as vertebrates
and fungi. Thus, they concluded that the likelihood of DNA being preserved in amber was minimal, but
such negative results cannot disprove its existence. Kimberly et al. (1997) were unable to replicate DNA
extraction from Dominican amber Propblebeia, despite using nine specimens and nested amplifications,
which greatly enhanced the sensitivity of the assay process. Stankiewicz et al. (1998) found that relatively
resistant macromolecules, such as lignin, cellulose and chitin were extremely degraded in Dominican amber
plant and insect inclusions, concluding that the persistence of fragile molecules such as DNA would be highly
improbable.
This century, more recent claims (Rogers et al., 2000) have proposed that rapidly dehydrated inclusions
may contain undamaged DNA. However, Hebsgaard et al. (2005) pointed out that many research groups
currently accept one hundred thousand to one million years as the maximum age range for DNA survival,
based on both theoretical and empirical data, and that despite the problems associated with modelling the
long-term survival of DNA in the geosphere, the claims of DNA from amber (1,000-fold older than theoretical
predictions for maximal DNA survival) are cause for concern, regardless of how good a preservative the natural
resin is. According to these authors, all claims for amber DNA to date suffer from inadequate experimental
design and insufficient authentification criteria. Some of the earlier proponents for DNA extraction have now
held up their hands and admitted that it looks like the end of the road for fossil DNA, whereas others still
support their findings; the burden of proof now lies with the latter. The jury is still out on whether or not it
is possible to extract DNA from amber, or indeed whether it remains in tact in fossilized resin, but given the
evidence to hand it would seem unlikely.
A particularly interesting study by Koller et al. (2005) used a new technique for internal fixing of
amber inclusions in association with electron microscopy and histochemical staining. They noted that cellular