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CTENOPODA, SARS, 1865 (infraorder)

 

SIDIDAE, BAIRD, 1850 (family)

 

Second antenna with dorsal branch 2-segmented and ventral branch
3-segmented. Both branches together with more than 10 setae.
6 pairs of similar legs.

 

DIAPHANOSOMA FISCHER 1850
Planktonic in lakes. Food phytoplankton.
The genus has been revised recently by Korovchinsky
(1991, 1998, 2000).
See key to species in Korovchinsky (1992 + supplemented with 1998)
 - Calibato Lake, Sampaloc Lake
Diaphanosoma sp.
   [Unpublished data (1979-80)]

Diaphanosoma sp. from Calibato Lake

Diaphanosoma sp, Taal Lake
(Photo: Rey Donne S. Papa, 2007)

 

88 a. Distinct wide, free flap-shaped inflexion (duplicature)
on ventral margin of shell (carapace/valve) present..........90

 

88 b. No distinct free flap (duplicature) (See Fig. 90 a)
on ventral margin of shell, only narrow inflection...........89

 

TABLE: The morphological differences between D. orghidani, D. modigliani, D. tropicum and D. dubia. Se Korovchinsky (1998+2002b) and Weiler (1998)

 

Species:

D. orghidani transamurensis (89a)

D. modigliani (89b-note)

D. tropicum
(89b)

D. dubium
(89c)

Traits:

0

Status in the Philippines

Recorded

Philippine records now regarded as
D. tropicum

Recorded

Recorded

1

Head

 

 

 

Head small, rectangular, with well-developed, high dorsal part not protruding. 

Head large, protruding dorsally, less than half of shell length

Head large, protruding dorsally, less than half of shell length

Head very large, more massive, protruding dorsally, nearly half the length of shell

2

Spine on the end of upper antennal branch

 

Short acute

Slightly curved or straight

Strongly curved

Extremely variable. Straight to strongly curved

3

Ventral shell (valve) fold (inflexion)

 

Small ventral inflection of shell noticeable shifted proximal

Comparatively short and shifted proximal

Comparatively long and not shifted proximal

Large, narrow

4

Denticles of ventro-posterior valve margin

 

 

 

Few: 19-32 (more often 22-29) in ssp.  transamurensis,

Small and very numerous:
55-86

Comparatively large and not very numerous:
25-43
(min.-max. range 22-58)

Small and very few: 12-29 (min.-max. range 8-40)

5

Postabdomen and terminal claws

 

 

Dorsal part not prominent.

Dorsal part not prominent, basal spines short

Dorsal part prominent, basal spines comparatively long

Dorsal part prominent.

6

Head length: Body length (%)

 

39,0

39,8

44,6

49,7
(min.-max. range 44,1-52,1)

7

Diameter of eye: Body length (%)

 

9,0
(moderate to large size)

6,6

7,8

7,4-11.1

8

Length of 2nd antenna: Body length (%)

76,5 ssp. orghidani

 

69,6

63,7

61,4 (Philippines:

65,2-78,3)

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