New data on the morphology and distribution of Euglandina obtusa (Pfeiffer, 1844) (Gastropoda: Spiraxidae) a Nicaraguan endemism

2008·2.3 MB·English

by  Mijail A Perez

©SociedadEspañoladeMalacologta Iberus, 26 (2): 127-131, 2008
New data on the morphology and distribution of
Euglandina obtusa (Pfeiffer, 1844) Gastropoda: Spiraxidae)
a Nicaraguan endemism
Nuevos datos sobre la morfología y la distribución de Euglandina
obtusa (Pfeiffer, 1844) (Gastropoda: Spiraxidae) un endemismo de
Nicaragua
MijailA. PÉREZ*, KepaALTONAGA** andAdolfo LÓPEZ***
Recibidoel24-IV-2008.Aceptadoel25-VI-2008
ABSTRACT
Aspects related to the morphology and distribution of Euglandina obtusa (Pfeiffer, 1844) a
Nicaraguan endemism are presented. Regarding morphology, a complete redescription of
the shell and the first description ofthe genital system are included. The number of records
has been increased, from one, the type locality, to 16. Current data have allowed us to
draw a distribution map ofthe species in Nicaragua.
RESUMEN
Se presentan aspectos relacionados con la morfología y la distribución de Euglandina
obtusa (Pfeiffer, 1844) un endemismo de Nicaragua. En relación con la morfología, se
presenta una redescripción de la concha y la primera descripción del aparato genital. El
número de registros de la especie en el país ha sido incrementadade una a ló localida-
des. Las cifras anteriores nos han permitido elaborar un mapa preliminar de distribución
para la especie en Nicaragua.
KEYWORDS:Newdata,Euglandinaobtusa Gastropoda, Spiraxidae,Nicaragua,Endemism.
,
PALABRASCLAVE:Nuevosdatos,Euglandinaobtusa, Gastropoda, Spiraxidae,Nicaragua,Endemismo.
INTRODUCTION
According to Pilsbry (1908), Pilsbry In the Nicaraguan Pacific Slope the
and Vanatta (1936), Baker (1945) and genus Euglandina is represented by two
Thompson (1995), the genus Euglandina species: Euglandina cumingii (Beck, 1837)
Fischer and Crosse, 1870 contains 92 and Euglandina obtusa (Pfeiffer, 1844). E.
species along its distribution range. obtusa is a species endemic to
According to Zilch (1959-60), the distri- Nicaragua, only known to date from the
bution of this genus ranges from South- type locality. Realejo, in the department
ern North America to northern South of Chinadega (UTM 16PDU8286); the
America, includingCentralAmerica. only information existing about this
*AsociaciónGaia,Colonia 10deJunio, B-501,Managua,Nicaragua.
** Departamento de Zoología y Dinámica Celular Animal, Universidad del País Vasco/ Euskal Herriko
Unbertsitatea, Bilbo,España.
***CentrodeMalacologíayDiversidadAnimal, UniversidadCentroamericana,Managua,Nicaragua.
127
Iberus, 26 (2), 2008
Figure 1. Euglandina obtusa. Shell morphology. Cayanlipe, Chínandega, 97:84 (D 11,26 mm,Alt.
27.15 mm). Figure2. Genitalsystem. Cayanlipe, Chinandega, 97:84 (e= 1 mm).
Figure 1. Euglandinaobtusa. Morfologíadelaconcha. Cayanlipe, Chinandega, 97:84(D 11.26mm,
Alt. 27.15mm). Figura2.Aparato reproductor. Cayanlipe, Chinandega, 97:84(e- 1 mm).
taxon so far was a brief description of shell biometry and the first description
theshell(Pérez, 1999). ofthegenitalsystemisalsogiven.
The citations for this species in the
XIX century literature can be summa-
rizedasfollows: MATERIALAND METHODS
Glandina obtusa Pfeiffer, 1844, in
Philippi (1842-1845), p. 132, pl. 1 fig. 3. Source ofdata: Data presented in this
Achatina obtusa: Reeve (1849 in 1848- paper have been taken from Pérez
1850), Monograph of the genus (1999); this work has been based on
Achatinapl. 15, species62. gathering, comparison and synthesis of
Achatina obtusa: Deshayes (1850) in information from two main sources: In
Férussac and Deshayes (1819-1851), p. the first place, data obtained from revi-
173, pl. 134figs. 3,4. sión ofbibliography regarding land and
Oleacina obtusa: Tryon (1885), p. 24, freshwater snail species present in
pl.4fig. 55 Nicaragua and Central America and,
Glandina obtusa: Martens (1891 in secondly, field data obtained from four
1890-1901), pp. 76-77. majorsamplingcampaigns.
Euglandina obtusa: Pilsbry (1908 in Samplings: Sampling campaigns
1907-1908), p. 204. were carried out as follows: 1) Decém-
In this paper we present new data ber 1994 to March, 1995, 2) August-Sep-
on distribution and morphology for E. tember, 1996, 3) September-December,
obtusa. Fifteen new localities are added 1997 and, 4) July-October, 1998. Field-
to the one previously known. Data on workwas done as one-day trips, collect-
128
:
PÉREZETAL.: Morphologyand distribution ofEuglandina obtusa
TableI.Euglandinaobtusa. Dimensions.X:Average, DS: StandardDeviation.
TablaI. Euglandinaobtusa. Dimensiones.X:Promedio, DS:Desviaciónestándar.
Variable X Mínimum Máximum Range DS
Height 24.81 22.2 27.15 4.95 2.19
Diameter 10.5 10.1 11.3 1.2 0.49
Table II. Examined material (52 specimens, 19 live, 33 shells). Dp: department, Coord: coordina-
UTM
tesin notation, Ev: animáis, C: shells.
TablaII. Materialexaminado (52ejemplares, 19vivos, 33 conchas). Dp:Departamento, Coord: coor-
denadasennotación UTM, Ev:ejemplaresvivos, C:conchas.
Dp Lot Locality Coordinates Ev C
—
LE 96:40 ElBosque 16PEJ2496 —1
LE 96:50 3kmalNEdeElEmpalme 16PEK6504 —3
LE 96:54 BuenosAires 16PEJ0169 — 2
LE 96:67 CarreteraElSauce-Estelí 16PEK5432 — 2
CH 97:56 19deJulio(PasoCaballo) 16PDJ7986 — 1
CH 97:75 ElRincón 16PEK2328 — 1
CH 97:76 Mayocundo 16PEK2515 — 2
CH 97:78 km 194Chinandega-Somotillo 16PEK1237 — 1
CH 97:81 km 166Chinandega-Jiquilillo 16PDK5706 —6
CH 97:82 Tomvalle 16PDK6704 —2
CH 97:84 Cayanlipe 16PEK0927 — 4
CH 97:85 LaConcepción 16PEK3122 — 1
CH 97:86 LasGarzas 16PEK3325 3
CH 97:92 Hilocán 16PDK3721 7 2
CH 97:93 LaberintodeSanJuan 16PDK3422 7 7
ing at various points each day. A alcohol, in the case of live-taken speci-
mínimum of one point per 10 x 10 km mens, or in glass vials within cardboard
quadrantwas sampled, and a máximum boxes, inthecaseofemptyshells.
of three points. The quantity of points Abbreviatures The following abbrevi-
was determined by the punctual species ations have been used: B.C.A.: Biología
richness; if it was low (below three Centrali Americana, Carr.: Road, e:
species) we sampled another point scale, p./ pp.: page/ s, s.l.p.c.: without
within the same quadrant. There were an exact locality consigned, RAAN:
four persons collecting for an hour at Región Autónoma del Atlántico Norte,
eachsamplingpoint. RAAS: RegiónAutónoma del Atlántico
Collection and conservation ofmaterial: Sur, UCA: Universidad Centroameri-
Material was hand-collected, kept in cana.
plástic boxes and labeled for taking to
the lab. Living specimens were relaxed
in water with menthol crystals for 24 RESULTS ANDDISCUSSION
hours and then stored in 70° alcohol.
Once fixed, material was separated, Description:Shellcylindrical-fusiform,
identified and definitively stored in opaque,solid,glossy(Fig. 1).Spirerepre-
glass vials within glass jars with 70° sents a little less than 1/3 of total shell
129
:
Iberus, 26 (2), 2008
Figure3. Euglandinaobtusa. Distribution inNicaragua, in UTM notation of30x 50 kmandwith
mentionofthetypelocality(ElRealejo).
Figura3. Euglandina obtusa. Distribución en Nicaragua, en notación UTMde50x50km de lado
con mencióndelalocalidadtipo (ElRealejo).
mm
length. Colourbrown. Sculpture of fine and 19 in height and more or less
radial folds. Suture slightly marked. half the width; itwas first described by
Apex obtuse. Whorls 6, moderately Pfeiffer (1844) inPhillippi (1842-1851),
convex. Base imperforate.Aperture long and is the one represented in Pfeiffer's
and ovate, placed laterally regarding the collection; according to Martens
shell axis; it represents approximately (1891), this is the form which he
1/3 ofthebody whorl height. Peristome studiedm.mThe larger form, measuring 26
simple and not reflexed. Columella to 28 and being half as wide as
curved and truncated, somewhat thick- high, is the one depicted by Reeve
ened. Protoconch ofa white to corneous (1849) andDeshayes (1850)inFérussac
colour,smooth,whorls1.5. and Deshayes (1819-1851); this form
Dimensions Alt. 27.15 mm, D. 11. 26 resembles very much in its dimensions
mm
(seeTableI). Euglandina largilliertiPilsbry, 1891, from
Genital apparatus with a long Guatemala and Yucatán, but seems to
brawny penis (Fig. 2); retractor muscle be smoother andbrighter.
wide and short; vas deferens attached to Tryon (1885) recognized only the
the penis and to the vagina by conjun- dimensions of the larger form (26-28
tive stripes. Vagina short in relation to mm), as relevant to E. obtusa. Later,
the penis and as wide as its proximal Pilsbry (1908 in 1907-1908), referred to
part. Bursa copulatrix rather small and Tryon's (1885) description and added
club-shaped, ductlongandthin. that this species seems to link the group
Remarks: Martens (1891 in 1890- of the smooth Central American forms
1901) pointed out that though descrip- tousualEuglandina.
tions and pictures all cite Realejo (also Our material agrees which what
written as Real Llejos) as the locality in would be the larger "form" mentioned
which the species was collected, they by Martens (1891), although with
referred to two different forms, slightly smaller dimensions. Its smooth
showing differences in size and shape. and lustrous shell sculpture makes the
The smallest one measures between 16 Identificationofthisspeciesveryclear.
130
.
PÉREZETAL.: Morphology and distribution ofEuglandina obtusa
The genital system of this species is gestsaveryrestricteddistributionrange.
described for the first time in this paper, This may be confirmed also by the fact
and as this taxonwasknownpreviously that it has not been collected so far else-
only from the type locality, all distribu- whereinthecountryovertheyears.
tion data given in this paper are new Along its distribution range E.
andexpandconsiderablyitsdistribution obtusa was collected on road edges, in
range. dry forests ranging from savannah
Distribution: This species was previ- forests with abundant shrubs to low-
ously cited only from the type locality, medium semideciduous secondary
but we have added 15 new localities to forests. Soil was covered by abundant
the one cited in the literature (Fig. 3, leaflitter, withorwithoutsand and wet,
Table II). New localities are distributed and illuminationwas offiltered sun and
in two departments (= provinces) (Dpt. shade.
of Chinandega and Dept. of León) of It should also be pointed out that E.
northwesternNicaragua,bothwithinthe obtusa is a rare species, since lots col-
Nicaraguan Pacific Slope, which sug- lectedconsistonlyof1 to 14specimens.
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