３－４ Krenosmittia group (anal setae(1 or 2) long , about half of body length)
return to Orthocladiinae group
Krenosmittia Pseudorthocladius Parachaetocladius
| mentum | antenna | mandible | prenmandible | anal setae | |
| Krenosmittia | Pointed large median tooth , 6 pairs.of pointed lateral teeth. | 4 segments : segment 3 and 4 very short. | apical tooth as wide as 3 combined inner teeth. |
divided deeply into 3 | anal setae 4or 5, of which 1 or 2 are 1/3～1/2 length of body . |
| Pseudorhthocladius | 2 large median teeth, 4 pairs of lateralteeth. | 5 segments; Lauterborn's organ comparatively large. | apical tooth nomal, lateral teeth 3. |
simple spatula shape | anal seta 1, 1/3～1/2 length of body |
| Parachaetocladius | 2 large median teeth. 4 pairs of lateral teeth. | 5 segments; Lauterborn's organ comparatively large. | apical tooth nomal, lateral teeth 2 . |
simple spatula shape | anal seta 1, longer than 1/2 length of body |
small size larvae ; up to ４mm long. , several species found in the country.. I think there are 2 types about larva according to form of SⅡ．
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| Median tooth as wide as 3 lateral teeth combined. 6 pairs of pointed lateral
teeth. Ventromental plate small , not extending beyond outer tooth of mentum.下 |
Narrow pointed , apical tooth longer than combined width of 3 inner teeth. Seta subdentalis long and narrow. | |
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１：Head: eye spot situated backward ２：mentum ３：mandible ４：Antenna with 4 segments, segment 3and 4 very short ５：ＳⅠ: apex divided into 3 or simple. ６：ＳⅡ:long needle like ７：Pecten epipharyngis : 3 long lobes ８：Premandible : dibided into 3 deeply ９：end of boby １０：Claws of anterior parapod １１：Claws of posterior parapod １２：Anal tubules: short conical. １３：Anal setae: 2 long setae and 3 short setae. |
| anal setae 3 or 5, of which 1 or 2 are 1/3～1/2 length of body . |
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Pseudorthocladius |
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| Lateral teeth with 4 pairs, Ventromental plate very small. | Antenne 5 segments, length of combined 3rd～5th segments shorter than segment
2 , blade extending as far as terminal segment. Lauterborn's organ large.
Mandible with 3 inner teeth. |
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 Anal seta 1Anal tubules and Postrior parapods situated under segment 12. |
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・2 median teeth and 4 pairs lateral teeth ・Antenna : 5 segments, blade beyond terminal segment. ・ＳⅠ: serratered edge, ＳⅡ: long needle like. ・Anal seta 1/2～2/3 of body length. ・Anal tubules and Postrior parapods situated under segment 12. Pseudorthcladius : mandible with 3 inner teeth. Parachaetocladius with 2 inner teeth. |
3 species found in the country.
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| Median tooth of mentum ; 2 poorly separated. , 4 pairs of lateral teeth. | mandible with 2 inner teeth . | |
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Parachaetocladius and Pseudorthocladius are difficult to distinguish because forms of mentum and antenna are similar. ・Antenna with 5 segments, blade beyond terminal segment. ・Pecten epipharyngis : 3 small lobes( left fig.) or 3 large lobes . |
| Anal tubules and Postrior parapods situated under segment 12. 1 anal seta up to 1/2 body length. |