Workshop on peracarid crustaceans, October 2005

Lectures given

Oct. 18, 2005    Introduction

Oliver Coleman: Describing biodiversity! Do we need a new taxonomy?

Unpublished species

Angelika Brandt: Biodiversity and zoogeography of Southern Ocean deep-sea Isopoda (Crustacea, Malacostraca) - Results from the ANDEEP I-III expeditions

Claude DeBroyer: Implementing SCAR-MarBIN - The Antarctic Marine Biodiversity Information Network

Oct. 19, 2005    Standards for species descriptions

Marina Malyutina: Describing species

Jörundur Svavarsson: Standards for species descriptions - contents

Oct. 20, 2005    Techniques

Karl Wittmann: Fixation effects

Jürgen Guerrero-Kommritz: Mounting media and preserving specimens

Oliver Coleman: Digital illustrations

Christoph Held: New visualisation techniques in taxonomy and systematics.

Oct. 21, 2005    Cryptic species

Kim Larsen: How to deal with sibling species and polymorphism: a case story

Describing species

Species descriptions must follow the ICZN.

A species description or redescription should contain the following sections:

•     heading 

• o should give a classification

• synonomy

• o not a full account of all records of the species

  o limited to publications containing data that is significant to the taxonomy

  o if possible, citation of catalogues

  • material examined

  o should include information about fixation and preservation

  o indicate locus typicus and deposition of types in a museum with public access, preferably in more than one museum

  o in (re)descriptions the full information about the type material examined should be noted (e.g. condition, date and locality of collection, name of the collector, catalogue number, name of the institution)

  • etymology
  • diagnosis

  o even in monotypic species

  o should contain the main diagnostic characters

  o the purpose of the diagnosis is the easy identification of the species

  • description
  • taxonomic discussion or remarks

  o should include a differential diagnosis

  o should reflect difficulties and doubts during the description

  It may also contain information about

  • ecology
  • distribution

  For a species description the following important points should be considered:

  Dissection

  • if a new species is represented by a single specimen alone, a description (and dissection) might be useful if the species description will add essential taxonomic/systematic/phylogenetic information
  • the holotype should not be dissected, unless
  • only a single specimen is present
  • it is definitely possible to dissect it without damaging it
• as much as possible, characters of the holotype should be illustrated

  Text

  • as precise as possible, all segments and appendages should be addressed
  • characters, which we do not consider as very important, might well become interesting for future taxonomic or phylogenetic work
  • variations and other additional information can be addressed within the text
  • family and generic characters can be omitted, if a generic/family description is included or cited
  • include length proportions

  Drawings

  • habitus dorsal and lateral, other orientation if necessary, always before dissection
  • the head should receive special attention, because it may provide a number of useful characters
  • all appendages should be illustrated, the legs should not be neglected, even if they seem to be all similar
  • illustrate voluminous structures from different aspects to provide details about the 3-dimensional structure
  • avoid distortion during mounting
  • a consistent orientation and sequence is preferable, but not always possible

  SEM-Pictures

  • are a useful addition to traditional taxonomic methods, but cannot replace drawings, because

  o comparability is not ensured

o structures can not be illustrated from all desired angles

Digital photographs

• might be useful as an addition, e.g. to illustrate colours, but are not suitable to illustrate fine structures

3-D visualisation

• non-destructive
• additional information that can not be obtained with traditional methods

Variation

• Variations should be investigated and documented carefully
• to establish a fundamental level of polymorphism is also crucial for the investigation of sibling species

Deposition of the types

• the method of preservation of the types (including the slides) should be carefully chosen with respect to long-term storage and future use

Standardised nomenclature for all peracarids

The challenge of merging the many different ways of naming homologous morphological characters in different peracarid groups was met with enthusiasm and success, at least in part, as can be seen in the table below.

 

1. head/cephalothorax and limbs

limb, limb structure	Amphipoda	Cumacea	Isopoda	Mysidacea	Tanaidacea	consensus	comments
cephalon, head	cephalon (fused with carapace)	cephalon , head	cephalon , head	cephalon (fused with carapace)	cephalon	always cephalothorax because at least one thoracic segment is fused with the head
cephalothorax	cephalothorax	cephalothorax	cephalothorax	cephalothorax	cephalothorax
antenna 1	antenna 1 , antennula	antenna 1 , antennula	antenna 1 , antennula	antenna 1, antennula	antenna 1, antennula	antenna 1
peduncle	peduncle , peduncular articles 1-3	peduncle , article 1-3	peduncle , article 1-3	peduncle , antennular trunk	articles 1-3 , peduncle	peduncle
flagellum	flagellum	flagellum	flagellum	inner flagellum	inner flagellum	flagellum
appendix masculina	absent	absent	absent	appendix masculina	absent	non-homologous structures
accessory flagellum	acessory flagellum	acessory flagellum	absent	outer flagellum	outer flagellum	non-homologous structures
absent	absent	absent	accessory flagellum	absent
callynophore	callynophore	absent	absent	absent	absent	apomorphy of Amphipoda
antenna 2	antenna 2 , antenna	antenna 2 , antenna	antenna 2 , antenna	antenna 2, antenna	antenna 2, antenna	antenna 2
antennal scale	absent	absent	squama	antennal scale	squama	squama
peduncle	peduncle , peduncular articles 1-5	peduncle	peduncle , article 1-6	antennal sympod , peduncle (basischium, praecoxa, coxa)	peduncle, articles 1-7	peduncle
flagellum	flagellum	flagellum	flagellum	flagellum	articles	flagellum
epistome	epistome , clypeus	absent	clypeus	absent	epistome	epistome
labrum	labrum, upper lip	absent	labrum	labrum	labrum	labrum
mandible	mandible	mandible	mandible	mandible	mandible	mandible
palp	palp	absent	palp	palp	palp	palp
incisor	incisor , pars incisiva	incisor , pars incisiva, incisor process	incisor , pars incisiva, incisor process	incisor, pars incisiva, incisory process	incisor , pars incisiva	incisor
molar	molar , pars molaris	molar , pars molaris	molar , pars molaris	molar , pars molaris	molar , pars molaris	molar
lacinia mobilis	lacinia mobilis	lacinia mobilis	lacinia mobilis	lacinia mobilis	lacinia mobilis	lacinia mobilis
setal row	setal row , spine row, raker setae	setal row	setal row , spine row	setal row , pars centralis, spine row	setal row	setal row
Mandibular body	mandibular body	mandibular body	mandibular body	mandibular trunk	mandibular body	mandibular body
labium	labium, lower lip, hypopharynx, paragnath	labium	hypopharynx	labium , lower lip	labium	labium
maxilla 1	maxilla 1 , maxillula	maxilla 1 , maxillula	maxilla 1 , maxillula	maxilla 1, maxillula	maxilla 1, maxillula	maxilla 1
sympod	sympod	sympod
inner plate	inner plate , inner lobe, basal endite	inner endite	inner lobe, mesial lobe, inner endite	endopod	inner endite	homology problematic, especially in Mysidacea
outer plate	outer plate , outer lobe, ischial endite	outer endite	outer lobe, lateral lobe, outer endite	exopod	outer endite
palp	palp	palp	absent	absent	palp	palp
maxilla 2	maxilla 2 , maxilla	maxilla 2 , maxilla	maxilla 2 , maxilla	maxilla 2, maxilla	maxilla 2, maxilla	maxilla 2	homology problematic, especially in Mysidacea
inner plate	inner plate , inner lobe, basal endite	inner endite	inner lobe, mesial lobe, inner endite	endopod	inner endite
endites	endites
oblique setal row	oblique setal row, facial row	absent	absent	absent	absent
outer plate	outer plate , outer lobe	outer endite	outer lobe, outer endite, lateral lobe	exopod	outer endite
medial lobe	medial lobe	medial lobe , medial endite

2. Thorax/pereon and limbs

limb, limb structure	Amphipoda	Cumacea	Isopoda	Mysidacea	Tanaidacea	consensus	comments
thorax	thorax	thorax	thorax	thorax	thorax
pereon	pereon	pereon	pereon	pereon	pereon
absent	carapace	absent	carapace	carapace	carapace
thoracopod 1	maxilliped	maxilliped 1	maxilliped	thoracopod 1 , maxilliped 1	maxilliped	traditionally different terminology
thoracopod 2	gnathopod 1 , pereopod 1, cheliped	maxilliped 2	pereopod 1 (pylopod)	thoracopod 2, maxilliped 2, (pereopod 1)	cheliped
thoracopod 3	gnathopod 2 , pereopod 2,	maxilliped 3	pereopod 2	thoracopod 3 , pereopod 1, (pereopod 2)	pereopod 1
thoracopod 4	pereopod 3	pereopod 1	pereopod 3	thoracopod 4 , pereopod 2, (pereopod 3)	pereopod 2
thoracopod 5	pereopod 4	pereopod 2	pereopod 4	thoracopod 5 , pereopod 3, (pereopod 4)	pereopod 3
thoracopod 6	pereopod 5	pereopod 3	pereopod 5	thoracopod 6 , pereopod 4, (pereopod 5)	pereopod 4
thoracopod 7	pereopod 6	pereopod 4	pereopod 6	thoracopod 7 , pereopod 5, (pereopod 6)	pereopod 5
thoracopod 8	pereopod 7	pereopod 5	pereopod 7	thoracopod 8 , pereopod 6, (pereopod 7)	pereopod 6
praecoxa	absent	absent	praecoxa	praecoxa	absent	praecoxa
coxa	coxa , article 1	coxa	coxa	coxa	coxa	coxa
basis	basis , article 2	basis	basis	basis	basis	basis
ischium	ischium , article 3	ischium	ischium	ischium	ischium	ischium
merus	merus , article 4	merus	merus	merus	merus	merus
carpus	carpus , article 5	carpus	carpus	carpus	carpus	carpus
propodus	propodus , article 6	propodus	propodus	propodus	propodus	propodus
dactylus	dactylus , article 7	dactylus	dactylus	dactylus	dactylus	dactylus
claw	claw , unguis	claw	claw , unguis	claw , nail	unguis , claw	unguis	Latin term consistent with terms for other limb segments
marsupium	marsupium , brood pouch	marsupium , brood pouch	marsupium brood pouch	marsupium , brood pouch	marsupium , brood pouch	marsupium
oostegites	oostegites, brood plates	oostegites, brood plates	oostegites	oostegites, brood plates	oostegites, brood plates	oostegites

3. Abdomen/pleon/pleotelson and limbs

limb, limb structure	Amphipoda	Cumacea	Isopoda	Mysidacea	Tanaidacea	consensus	comments
pleon	pleon	pleon	pleon	pleon	pleon
pleonites , pleosomites	pleonites	pleonites	pleonites	pleonites	pleonites
pleopod 1	pleopod 1	pleopod 1	pleopod 1	pleopod 1	pleopod 1	pleopod 1
pleopod 2	pleopod 2	pleopod 2	pleopod 2	pleopod 2	pleopod 2	pleopod 2
appendix masculina (stylet)	gonopod (different pleopods)
pleopod 3	pleopod 3	pleopod 3	pleopod 3	pleopod 3	pleopod 3	pleopod 3
urosome , abdomen, uron	traditionally different terminology
uronites, urosomites		pleonites 4-5	pleonites 4-5	pleonites 4-5	pleonites 4-5
pleopod 4		uropod 1	pleopod 4	pleopod 4	pleopod 4	pleopod 4
pleopod 5		uropod 2	pleopod 5	pleopod 5	pleopod 5	pleopod 5
urosomite 3		pleomer 6	pleotelson (pleomer 6 & telson)	pleomer 6	pleotelson (pleomer 6 & telson)
uropod		uropod 3	uropod	uropod	uropod	uropod	uropod
protopod	peduncle	protopod , peduncle	peduncle, protopod, sympod	sympod , peduncle	protopod, basal article, peduncle	protopod
exopod	exopod, outer ramus	exopod , outer ramus	exopod , outer ramus	exopod	exopod	exopod
endopod	endopod, inner ramus	endopod , inner ramus	endopod , inner ramus	endopod	endopod	endopod
telson	telson	pleotelson (pleomer 6 & telson)	telson	pleotelson (pleomer 6 & telson)	telson

 

---

---

 

---

---