Chrysothrix galapagoana, a new species from the Galapagos Islands

Abstract

Chrysothrix galapagoana is described from the Galapagos Islands where it is considered to be endemic. It is most similar to the fertile species C. placodioides, described from historical collections from Brazil, but differs in having smaller mature pseudo-areolate granules and in reproducing asexually from granules usually produced on the upper surface of the thallus.

Full text

174
Opuscula Philolichenum, 12: 174–179. 2013.
*pdf effectively published online 7November2013 via (http://sweetgum.nybg.org/philolichenum/)
Chrysothrix galapagoana, a new species from the
Galapagos Islands
KERRY KNUDSEN 1AND FRANK BUNGARTZ2
ABSTRACT. – Chrysothrix galapagoana is described from the Galapagos Islands where it is
considered to be endemic. It is most similar to the fertile species C. placodioides, described from historical
collections from Brazil, but differs in having smaller mature pseudo-areolate granules and in reproducing
asexually from granules usually produced on the upper surface of the thallus.
KEYWORDS. – Arthoniales, Ecuador, sterile crusts, South America.
INTRODUCTION
This study is a result of a general lichen inventory of the Galapagos Islands (Bungartz et al. 2009a,
2013) by the Charles Darwin Foundation (CDF). The Galapagos Archipelago comprises more than 123
oceanic islands, islets and large rocks that emerged from the sea as a result of volcanic hot spot activity; 14
islands are somewhat arbitrarily recognized because of their size as the principal islands (Snell et al. 1995,
1996). The Galapagos climate is unusually dry, with a hot and cool season and prevailing winds from the
south and southeast (Trueman & d'Ozouville 2010). Five principal vegetation zones can be distinguished:
coastal, dry, transition, humid, and high altitude dry (Bungartz et al. 2009b, Tye et al. 2002).
As part of the Galapagos Lichen Inventory the following islands have been visited and all
vegetation zones were surveyed: Isabela (Volcán Sierra Negra, Volcán Alcedo, Volcán Darwin, Volcán
Cerro Azul), Santiago (including Rábida, Bartolomé), Santa Cruz (including Santa Fé, Plaza Sur, Plaza
Norte, Roca Gordon, Pinzón), Pinta, Española, Floreana, and San Cristóbal. Among the many new
discoveries was a sterile yellow crust growing on basalt boulders in the dry zone, which we describe in this
paper.
The cosmopolitan lichen genus Chrysothrix Mont. (Chrysothricaeae Zahlbr., Arthoniales Hessen
ex D. Hawksw. & O.E. Erikss.) is currently comprised of 19 species (Laundon 1981a, 1981b; Mycobank
2013). Most species are only known as sterile crusts, few have been found fertile. The type of the genus is
C. chlorina (Ach.) J.R. Laundon. The species are generally characterized by a thallus of yellow to yellow-
green ecorticate granules of sizes up to 500 µm in diameter, but usually smaller, with a green algal
photobiont. Fertile species generally have immarginate apothecia with Arthonia-type asci and hyaline 3–7
septate ascospores. Most species contain pulvinic acid derivatives as the major secondary metabolites,
which give them their characteristic yellow color and inspired the etymology of the genus which means
“golden hair”. Only the recent addition to the genus, C. caesia (Flot.) Ertz & Tehler which was previously
placed in Arthonia, lacks these pigments (Ertz & Tehler 2011, Nelsen et al. 2009).
The modern revision of the genus began with the excellent work of J.R. Laundon (Laundon 1981a,
1981b). Since 1981, 11 new species have been described from around the globe (Elix & Kantvilas 2007,
Harris & Ladd 2008, Jagadeesh et al. 2006, Kalb 2001, Lendemer & Elix 2010, Thor 1988, Tønsberg 1994)
and four species have been transferred to the genus (Elix & Kantvilas 2007, Ertz & Tehler 2011, Harris &
Ladd 2008, Kalb 2001). Despite the progress in the revision of the genus, problems still remain.
Chrysothrix oceanica Räsänen was rightly excluded from the genus by Laundon as a Caloplaca because of
1KERRY KNUDSEN – Herbarium, Department of Botany and Plant Sciences, University of California,
Riverside, CA 92521-0124, U.S.A. – e-mail: kerry.knudsen@ucr.edu
2FRANK BUNGARTZ – Biodiversity Assessment, Charles Darwin Foundation (AISBL), Puerto Ayora,
Santa Cruz, Galapagos, Ecuador; postal address: Avenida Juan Gonzales N35-26 y Juan Pablo Sanz,
Quito, Ecuador. – e-mail: frank.bungartz@fcdarwin.org.ec or frank.bungartz@gmail.com

175
the presence of anthraquinones but the name is still legitimate (Laundon 1981b; Mycobank 2013). In our
opinion C. candelaris (L.) J.R. Laundon and C. chlorina are still heterogeneous and widely misapplied at
least in Europe and North America. More taxa new to science are expected to be discovered, especially
through the use of molecular analysis. In this paper we describe a new sterile species from the Galapagos
Islands, C. galapagoana, the twentieth species in the genus. So far the new species has only been found on
five of the Galapagos Islands surveyed during the Galapagos Lichen Inventory.
MATERIAL AND METHODS
Herbarium collections of the Galapagos Lichen Inventory are deposited at CDS; other Galapagos
specimens from historical collections were also reviewed (B, CAS, COLO, FH, H, OSC, S), but no material
of the new species was found among these collections. For comparison, non-Galapagos material of
Chrysothrix was also examined from CANB, NY, and UCR, as well as the holotype of C. placodioides
from S.
All specimens were examined with a Zeiss Stemi DV4 dissecting microscope and a Zeiss Imager
A1 compound microscope equipped with differential interference contrast. Macro-photos were taken with a
Nikon D300 and/or D7100, 62 mm Nikkor Micro Lens and R1C1 macro flash directly in the field, or using
a Novoflex macro-table to take images of herbarium specimens; for photographic magnifications higher
than 1:1 an extension tube or Novoflex bellows was used. For micro-photos the compound microscope is
equipped with a phototube for the Nikon D300/D7100. Photos in the laboratory were taken with Nikon
Camera Control Pro 2; all photos were databased with the program IDimager 5 using the Darwin Core
XML schema to embed collection and identification information as XMP metadata
(http://owl.phy.queensu.ca/~phil/exiftool/TagNames/DarwinCore.html). Photos were processed with
Photoshop CS4.
Thallus granules were measured in water. Standard spot tests were performed, including both 10%
and a stronger solution of potassium hydroxide (K). The terminology to describe leprose lichens follows
Lendemer (2011). The term “pseudo-areolate” or “pseudo-areoles” means appearing to be distinct corticate
areoles but actually being single unstratified ecorticate granules of large size.
Secondary metabolites were examined from a selection of specimens using standardized thin-layer
chromatography (Culberson & Ammann 1979; Culberson & Johnson 1982; Orange et al. 2001, 2010).
Instead of the conventional upright TLC tanks, a horizontal HPTLC developmental chamber was used
(Arup et al. 1993). TLC plates were documented with a Nikon D300 and/or D7100 digital camera. Photos
were taken immediately after running the solvent, in long wave (366 nm) and short wave (254 nm) UV
light, before applying 10% H2SO4. After H2SO4 treatment and charring in a laboratory oven for
approximately 8 min at 110ºC a second set of photos in daylight and short-wave UV (254 nm) were taken.
TAXONOMIC SECTION
Chrysothrix galapagoana K. Knudsen & Bungartz sp. nov.
Mycobank #806041.
TYPE: ECUADOR. GALAPAGOS ISLANDS: ISLA FLOREANA: ca. 500 m S of La Lobería,
ca. 200 m inland from coast, 1˚17′12.69″S, 90˚29′36″W, 20 m alt., dry zone, very open Bursera forest with
Waltheria ovata, few Scalesia affinis and some grasses on lava flow, on E-exposed front of lava flow,
sunny, wind- and rain-exposed, 16.i.2011, on rock, F. Bungartz 9756 (CDS 47073!, holotype; CDS!,
isotype).
DIAGNOSIS. – Similar to Chrysothrix placodioides, but differs in having granules generally much
smaller, (150–)170–250(–290) µm in diameter, and in reproducing asexually from granules usually forming
on the upper surface.
FIGURES 1A-C.

176
Figure 1. Pseudo-areolate growth of Chrysothrix galapagoana (A-C) and the type locality (D). A,
overview of the pseudo-areoles with subsquamulose tendencies along the thallus margin (Bungartz 9821;
scale 3 mm). B, detail of the thallus with granules forming on the surface of the pseudo-areoles (Bungartz
9756, holotype, scale 2 mm). C, thallus with less organized and more dispersed pseudo-areoles (Bungartz
5256; scale 5 mm). D, type locality of C. galapagoana: open Bursera graveolens forest (i.e., characteristic
dry zone vegetation) on a lava flow near the Floreana coast.
DESCRIPTION. – Prothallus of sparse thin vegetative hyphae, not apparent around mature granules,
unless thallus is damaged or eroded. Hypothallus lacking. Thallus of dispersed immature granules, very
compact, coarse, (35–)42–57(–70) µm in diam. (n = 30), or of large mature granules (150–)170–250(–290)
µm in diam. (n = 30), appearing pseudo-areolate, and producing immature granules on the upper surface
which could be mistaken as soredia and are ultimately dispersed. Upper surface bright neon yellow, large
granules pseudo-corticate, small granules ecorticate. Photobiont green, coccoid, 7–10 μm in diam.
Apothecia not observed. Pycnidia not observed.
CHEMISTRY. – Calycin (major) and ±pulvinic dilactone (minor). Spot tests P−, K+ faintly reddish
(10% solution), C−, KC−; UV− (dark).

177
DISTRIBUTION AND ECOLOGY. – The species is apparently endemic to the Galapagos Islands
(Espanola, Floreana, Isabela, San Cristóbal, Santiago) where it grows on basalt boulders, rocks and cliffs in
semi-shaded to sunny, exposed habitats. Most specimens were collected in the dry zone, but the species
also occurs in immediate proximity to the coast or in the dry, open forests of the lower transition zone
(figure 1D).
DISCUSSION. – Chrysothrix galapagoana is most similar to C. placodioides, described from
historical collections made by G.O. Malme in Brazil (Thor 1988). Like C. galapagoana, this species also
has pseudo-areolate granules but they are generally much larger (often over 500 µm in diameter, n = 10).
These granules have a smooth ecorticate surface and do not produce smaller immature granules on their
upper surface. No apothecia have been observed on C. galapagoana. Instead of reproducing asexually, C.
placodioides regularly produces apothecia. The thallus of C. placodioides looks more continuous and
pseudo-areolate than that of C. galapagoana, because new granules are also formed by vegetative division.
Chrysothrix candelaris as treated here contains calycin (major) and forms a distinctly leprose,
unstratified, non-areolate thallus, dispersed to continuous, with mature granules 100–200 μm in diameter
and immature granules from 10 μm in diameter, with a temperate distribution in Europe and not occurring
in North America (Elix & Kantvilas 2007, Harris & Ladd 2008, Kalb 2001, Laundon 1981b). Chrysothrix
galapagoana like C. candelaris produces calycin as a major secondary compound. It differs in having
larger mature granules ((150–)170–250(–290) vs. 100–200 µm). The large granules of C. galapagoana also
differ in being distinctly pseudo-areolate in appearance and in producing few to many immature granules
((35–)42–57(–70) μm) especially on the upper surface, which could be mistaken for soredia.
Three sterile species of Chrysothrix also produce calycin as a major or minor substance: C.
granulosa G. Thor, C. insulizans R.C. Harris & Ladd, and C. occidentalis Elix & Kantivalis. Chrysothrix
granulosa differs from C. galapagoana in producing diffractaic acid (major) in addition to calycin, having
a distinct hypothallus (treated as a medulla by Thor (1988)), and having smaller granules mostly 25–42 µm
in diameter (Thor 1988). Chrysothrix insulizans produces calycin as a major substance and is distinguished
from C. galapagoana by smaller granules (20–50 µm), a leprose thallus not becoming distinctly pseudo-
areolate, and in containing an unknown secondary substance (Harris & Ladd 2008). When Harris and Ladd
(2008) described this species they emphasized that the species often forms “soralium”-like patches that
resemble islands (etymology of insulizans: island-forming). Harris and Ladd (2008) did not discuss how
these patches were formed and in revising material of C. insulizans we concluded these patches are formed
by secondary aggregation of thallus granules. The “islands” are thus typical type 1 aggregated thalli of the
common caesioalba subtype of leprose lichens (sensu Lendemer (2011)) and must not be confused with the
pseudo-areolate growth of C. galapagoana, where large, mature granules themselves develop an “areolate”
appearance. Further, the aggregations of granules in C. insulizans are likely not of diagnostic value and
should not be stressed when identifying the species. Chrysothrix occidentalis, known from Australia and
Norfork Island in the Southern Hemisphere, differs from C. galapagoana in producing leprapinic acid as
the major substance with calycin only as a minor substance. Its thallus is not pseudo-areolate and is
composed of smaller granules (mostly 20–80 µm) (Elix & Kantivalis 2007).
The only other species of Chrysothrix reported from the Galapagos Islands is C. xanthina (Vain.)
Kalb (Bungartz et al. 2013). It produces pinastric acid as the major substance and has a leprose thallus of
smaller granules (20–40(–45) μm). This species generally grows on both bark and rock (Kalb 2001; Kukwa
& Knudsen 2011) and on those substrates it is also very common in the Galapagos, whereas C.
galapagoana has so far exclusively been collected on exposed rock surfaces. Chrysothrix xanthina was
recently reported new for Bolivia (Flakus et al. 2006). In the CDF Checklist of Galapagos Lichenized
Fungi, C. galapagoana was treated as Chrysothrix aff. occidentalis (Bungartz et al. 2013).
Additional specimens examined. – ECUADOR. GALAPAGOS ISLANDS: ISLA ESPAÑOLA:
trail from Bahía Manzanillo on the N-coast of the island to the highest point, dry zone, 1˚21′40.601″S,
89˚41′56.61″W, 48 m alt., open scrub of Cordia lutea and Prosopis juliflora with grasses and few trees of
Bursera graveolens over weathered lava boulders, 11-.xi.2010, on S-exposed front of basalt boulder, sunny,
wind- and rain-exposed, F. Bungartz 9095 (CDS 45913); 1˚21′24.89″S, 89˚41′57″W, 24 m alt., dry zone,
boulder field of weathered AA-lava with scarce vegetation of Ipomoea habeliana, one Bursera tree and few
Cordia lutea shrubs, 11.xi.2010, on SW-exposed front of small basalt rock, semi-shaded, wind- and rain-
exposed, F. Bungartz 9000 (CDS 45818), on W-exposed overhang of basalt boulder, shaded, wind- and
rain-sheltered, F. Bungartz 8990 (CDS 45808), on top of basalt boulder, sunny, wind- and rain-exposed, F.

178
Bungartz, 8981 (CDS 45799), on SSW-exposed front of basalt boulder, semi-shaded, wind- and rain-
exposed, F. Bungartz 8987 (CDS 45805). ISLA FLOREANA: between La Gigante and Playa de los Perros, a
little inland from coast, E-side of island, 1˚16′44.70″S, 90˚21′36.8″W, 56 m alt., dry zone, very open
vegetation of Cordia lutea with some Prosopis juliflora and other shrubs on NE-exposed slope with lava
boulders, 17-.i.2011, on top of small basalt rock, sunny, wind- and rain-exposed, F. Bungartz 9821 (CDS
47159). ISLA SAN CRISTÓBAL: Cerro Partido along trail from entrance to Cerro Pelado to El Ripioso,
0˚51′23″S, 89˚27′37″W, 376 m alt., transition zone, rocky SW-exposed slope of hill with Jasminocereus
thouarsii, Clerodendrum molle var. glabrescens, Psidium galapageium, Bromeliaceae and ferns growing in
rock crevices, 28.iv.2007, on top of basalt boulder, sunny, wind- and rain-exposed, F. Bungartz 6646 (CDS
34866); from Punta Tortuga ca. 3 km inland close to Cerro Tortuga, 0˚44′39″S, 89˚23′32″W, 79 m alt., dry
zone, young basalt lava flow of bare AA-lava, 25.iv.2007, on top of lava flow, sunny, wind- and rain-
exposed, F. Bungartz 6495 (CDS 34712), on top of “hornito”; sunny, wind- and rain-exposed, F. Bungartz
6493 (CDS 34710). ISLA SANTIAGO: ca. 4.5 km inland from the E-coast, ± at the same latitude as Bahía
Sullivan, 0˚16′51″S, 90˚37′10″W, 180 m alt., dry zone, lava field of older lava with scarce vegetation of
occasional Bursera graveolens trees, shrubs (Castela galapageia, Vallesia glabra var. pubescens,
Alternanthera filifolia) and Mentzelia aspera, 19.vii.2006, on E-exposed steep slope (80°) of basalt
boulder, sunny, wind- and rain-exposed, F. Bungartz 5256 (CDS 29471). ISLA ISABELA: Volcán Darwin,
southwestern slope, above Tagus Cove, 0˚13′43.29″S, 91˚19′47.29″W, 724 m alt., lower transition zone,
SW-exposed lava flow of weathered AA-lava with scarce vegetation (Macraea laricifolia, Dodonaea
viscosa, Croton scouleri, Cordia revoluta and Jasminocereus thouarsii), 12.xi.2007, on W-exposed front of
basalt boulder, sunny, wind- and rain-exposed, F. Bungartz 7406 (CDS 37893); lava field between Tagus
Cove and Caleta Negra at the W-coast of the island, ca. 500 m inland from the coast, 0˚14′44″S,
91˚22′55.89″ W, 12 m alt., dry zone, ragged lava field (AA-lava) bare of vegetation, 17.xi.2007, on SW-
exposed front of small basalt rock, sunny, wind- and rain-exposed, F. Bungartz 7968 (CDS 38478).
ACKNOWLEDGEMENTS
We thank an anonymous reviewer and Martin Kukwa (Poland) for their valuable comments on our
manuscript and we thank the curators of CANB, NY, and S for supplying material for comparison. Frauke Ziemmeck
has contributed to this study by managing the cryptogam collection at CDS, helping with collecting, data entry and
curation of specimens. Successive Directors of Science at the Charles Darwin Foundation have supported this project:
Alan Tye, Mark Gardener, Rodolfo Martinez, and Ulf Härdter. We are further indebted to the Galapagos National Park,
especially its technical director Washington Tapia for support and specimen export permits. The Census of Galapagos
Biodiversity and the CDF Checklist of Galapagos Species is supported by several grants to the Charles Darwin
Foundation (donors cited at http://www.darwinfoundation.org/datazone/checklists/). A checklist of Galapagos lichens
is regularly updated and available at http://www.darwinfoundation.org/datazone/checklists/lichens, where contributing
scientists are acknowledged. The lichen inventory continues to receive funds from The Paul and Bay Foundations and
repeatedly received funding from the Erwin Warth Stiftung. In 2010 an international lichen workshop was held in
Galapagos, supported by two National Science Foundation (NSF) projects (DEB 0715660 to The Field Museum; PI
Robert Lücking; and DEB 0841405 to George Mason University; PI James Lawrey, subcontract to the Charles Darwin
Foundation, local coordinator F. Bungartz). We much appreciate the help by G. Hillmann (Swedish University of
Agricultural Sciences) for analyzing specimens with HPTLC and John A. Elix (Department of Chemistry, Australian
National University) for help with interpreting our TLC results. This publication is contribution number 2079 of the
Charles Darwin Foundation for the Galapagos Islands.
LITERATURE CITED
Arup, U., S. Ekman, L. Lindblom and J.-E. Mattsson. 1993. High performance thin layer chromatography (HPTLC), an
improved technique for screening lichen substances. The Lichenologist 25(1): 61–71.
Bungartz, F., F. Ziemmeck, A. Yánez Ayabaca, F. Nugra and A. Aptroot. 2013. CDF Checklist of Galapagos
Lichenized Fungi. In: Bungartz, F., H. Herrera, P. Jaramillo, N. Tirado, G. Jiménez-Uzcátegui, D. Ruiz, A.
Guézou & F. Ziemmeck (eds.) Charles Darwin Foundation Galapagos Species Checklist. Charles Darwin
Foundation, Galapagos: http://checklists.datazone.darwinfoundation.org/true-fungi/lichens/. Last updated 16
Jan 2013.
Bungartz, F., H.W. Herrera, P. Jaramillo, N. Tirado, G. Jiménez-Uzcátegui, D. Ruiz, A. Guézou and F. Ziemmeck
(eds.) 2009a. Charles Darwin Foundation Galapagos Species Checklist. Charles Darwin Foundation, Puerto
Ayora, Galapagos: http://www.darwinfoundation.org/datazone/checklists/. Last updated 19 Feb 2013.
Bungartz, F., R. Lücking and A. Aptroot. 2009b. The lichen family Graphidaceae in the Galapagos Islands. Nova
Hedwigia 90: 1–44.

179
Culberson, C. and A. Johnson. 1982. Substitution of methyl tert-butyl ether for diethyl ether in the standardized thin-
layer chromatographic method for lichen products. Journal of Chromatography 238: 483–487.
Culberson, C. and K. Ammann. 1979. Standardmethode zur Dünnschichtchromatographie von Flechtensubstanzen.
Herzogia 5: 1–24.
Elix, J.A. and G. Kantvilas 2007. The genus Chrysothrix in Australia. The Lichenologist 39(4): 361–369.
Ertz, D. and A. Tehler. 2011. The phylogeny of Arthoniales (Pezizomycotina) inferred from nucLSU and RPB2
sequences. Fungal Diversity 49(1): 47–71.
Flakus, A., M. Kukwa, and P. Czarnota. 2006. Some interesting records of lichenized and lichenicolous Ascomycota
from South America. Polish Botanical Journal 51(2): 209–215.
Harris. R.C. and D. Ladd. 2008. The lichen genus Chrysothrix in the Ozark ecoregion, including a preliminary
treatment for eastern and central North America. Opuscula Philolichenum 5: 29–42.
Jagadeesh Ram, T.A.M., G.P. Sinha, R. Lücking, and H.T. Lumbsch. 2006. A new species of Chrysothrix (Arthoniales:
Arthoniaceae) from India. The Lichenologist 38(2): 127–129.
Kalb, K. 2001. New or otherwise interesting lichens. I. In: P.M. McCarthy, G. Kantvilas, and S.H.J.J. Louwhoff (eds.)
Lichenological Contributions in Honour of Jack Elix. Bibliotheca Lichenologica, J. Cramer, Berlin, Stuttgart,
pp. 141–167.
Kukwa, M. and K. Knudsen. 2011. Notes on the identity of Chrysothrix populations (Arthoniales, Ascomycota)
containing pinastric acid from southern and central California. Mycotaxon 116: 407–411.
Laundon, J.R. 1981a. Proposal to emend Chrysothrix Mont., nom. cons., and add Pulveraria Ach., nom. rej. (Lichens).
Taxon 30: 663–664.
Laundon, J.R. 1981b. The species of Chrysothrix. The Lichenologist 13: 101–121.
Lendemer, J.C. and J.A. Elix. 2010. Two new species of Chrysothrix from eastern North America. Opuscula
Philolichenum 8: 51–58.
Lendemer, J.C. 2011. A standardized morphological terminology and descriptive scheme for Lepraria
(Stereocaulaceae). The Lichenologist 43(5): 379–399.
Nelsen, M.P., R. Lücking, M. Grube, J.S. Mbatchou, L. Muggia, E. Rivas Plata and H.T. Lumbsch. 2009. Unraveling
the phylogenetic relationships of lichenized fungi in Dothideomyceta. Studies in Mycology 64: 135–144.
Mycobank. http://www.mycobank.org/ Accessed Aug. 7, 2013.
Orange, A., P.W. James and F.J. White. 2001. Microchemical Methods for the Identification of Lichens. British Lichen
Society, London. 101 pp.
Orange, A., P.W. James and F.J. White. 2010. Microchemical methods for the identification of lichens, second edition
with additions and corrections. British Lichen Society. London. 101 pp
Snell, H.M., P.A. Stone and H.L. Snell. 1995. Geographical characteristics of the Galapagos Islands. Noticias de
Galápagos 55: 18–24.
Snell, H.M., P.A. Stone and H.L. Snell. 1996. A summary of geographical characteristics of the Galapagos Islands.
Journal of Biogeography 23: 619–624.
Thor, G. 1988. Two new species of Chrysothrix from South America. The Bryologist 91(4): 360–363.
Tønsberg, T. 1994. Chrysothrix flavovirens sp. nov. - the sorediate counterpart of C. chrysophthalma. Graphis Scripta
6(1): 31–33.
Trueman M. and N. d’Ozouville. 2010. Characterizing the Galapagos terrestrial climate in the face of global climate
change. Galapagos Research 67: 26–37.
Tye A., H. L. Snell, S.B. Peck and H. Adersen. 2002. Outstanding terrestrial features of the Galapagos Archipelago. In:
R. Bensted-Smith (ed.) A biodiversity vision for the Galapagos Islands. Charles Darwin Foundation and
World Wildlife Fund, Puerto Ayora, pp. 25–35.