Zoology 250 Phylogenetic Trees (2017)


(water flea)

(gooseneck barnacle)
SUBPHYLUM CRUSTACEA
(see also an alternative molecular phylogeny)

(tree and most traits from:
Ruppert et al. 2004 p. 540, 668, 694,
Brusca et al. 2016 p. 833)


(mantis shrimp)

(amphipod)

(calanoid copepod)

(lobster)

       ====1============================= Remipedia
<<==C==|
       |   ===3========================== Cephalocarida
       =2==|
           |   ==5======================= Branchiopoda (fairy shrimp, water fleas, etc.)
           =4==|
               |   ==7=================== Maxillopoda (copepod, ostracod, barnacle, etc.)
               =6==|
                   |    ==8============== Phyllocarida (Or. Leptostraca)
                   =Mal=|
                        |      ==9======= Hoplocarida (mantis shrimps)
                        =Eumal=|
                               |    ==11= Peracarida (mysids,  amphipods, isopods, etc.)
                               =10==|
                                    ==12= Eucarida (krill, shrimps, lobsters, crabs, etc.)

Back to Zool 250 tree for animal phyla or Protostomia


TRAITS SUPPORTING EACH CLADE (** plesiomorphic- a primitive state, not unique to clade):
C= CRUSTACEA:
a) two pairs of antennae
b) first antennae uniramous**
c) second antennae biramous
d) mandible unbranched, 2 pair maxillae
e) sessile (non-stalked), compound eyes**
f) many similar, biramous, phyllopodous thoracic limbs**
g) telson with rami
h) nauplius larvae
i) naupliar eye= 4 fused median ocelli
j) 2 pair saccate nephridia only (segs. #2 & #5)
1= Remipedia:
a) first antennae biramous in adults
b) raptorial mouth appendages
c) segment #6= maxilliped
d) many similar trunk segments (thorax & abdomen not distinct)
    with paddle-like biramous legs
e) pre-antennal process
f) eyes lost
g) hermaphroditic
2:
a) 3 tagmata (head, thorax, abdomen)
b) 8 thoracic segments, maximum
3= Cephalocarida:
a) abdominal appendages lost
b) abdomen of 11 segments
c) segment #5= leg-like
d) compound eyes lost
e) hermaphroditic
4:
a) fully developed carapace
b) abdomen has fewer than 9 segments
5= Branchiopoda:
a) maxillae (segments #4) reduced/absent
    (trunk segment number & limbs vary greatly)
6:
a) thorax has fewer than 11 segments
b) abdomen has fewer than 8 segments
7= Maxillopoda:
a) thorax has fewer than 7 segments
b) abdomen has fewer than 3 segs., no limbs
c) unique naupliar eye (3-pigment cup ocelli)
d) lateral compound eyes lost
e) genital limbs on 1st abdomen somite of male
Mal= MALACOSTRACA:
a) thorax of 8 segments with similar limbs
b) abdomen of 7 segs. (with limbs) + telson
c) carapace covers head & thorax**
d) 1 antennae biramous in adult
e) stalked, compound eye
f) male gonopore on seg. #8, female on seg. #6
8= Phyllocarida:
a) 2 antennae uniramous in adult
b) abdomen of 7 segments + telson**
c) 2 maxilla like thoracic limbs**
d) similar, phyllopodous thoracic limbs**
Eumal= EUMALACOSTRACA:
a) exopodite of 2nd antenna is a large, flat scale
b) abdomen of 6 segments + telson
c) thoracic limbs stenopodous
d) long muscular abdomen
e) telson lacks rami
f) uropods + telson make a tail fan
9= Hoplocarida:
a) 2nd antennae triramous
b) carapace covers head & 4 thoracic segments
b) first 5 thoracic limbs uniramous & subchelate
c) thorax segment #2 with very large subchela
d) moveable rostrum
e) gills on pleopods
10:
a) carapace covers head & thorax (primitively)**
b) antennal statocyst
c) lacinia mobilis on left mandible only!
11= Peracarida:
a) carapace not fused with all head & thorax segments**
b) thoracic oostegites form brood chamber
c) pre-juvenile manca stage
12= Eucarida:
a) carapace fused dorsally with all head & thorax segments
b) 3 pair maxillipeds*
c) last 5 pair thoracic limbs uniramous*
d) well-developed gills under carapace*
e) brood eggs on pleopods*
f) zoea larval stage
* except euphausids


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Copyright (c) 2017 by A. Richard Palmer. All rights reserved.
(revised Dec. 19, 2016)