Corresponding author: Charles H.J.M. Fransen (
Academic editor: S. De Grave
Two new species of palaemonid shrimp associated with ascidian hosts,
de Gier W, Fransen CHJM (2018)
The palaemonid genus
In 2009 an expedition was organised by the Naturalis Biodiversity Center (Leiden, the Netherlands) and the Research Center of Oceanography, Indonesian Institute of Sciences (
The following abbreviations are used:
Specimens were gathered around Ternate, in the northern Moluccas during an expedition organised from 23 October to 18 November 2009, by the Research Center of Oceanography, Indonesian Institute of Sciences (
Specimens were studied and drawn using a dissecting stereomicroscope (Zeiss Discovery.V8) and a compound microscope (Olympus BX53) both provided with a drawing tube. Sketches were traced using 2.5 to 3 mm Sakura Pigma Micron-pens and scanned (Canon Canoscan 9000F) with a resolution of 600 dpi. Details of the third pereiopods were photographed with a Scanning Electron Microscope. Pereiopods were dried using Critical Point Drying-methods (
Morphological character state analysis (Appendix I) was based on specimens in the
Specimens used for SEM photography and
Species | Sample location | Host organism | Registration number | GenBank |
GenBank |
SEM |
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Indonesia, Halmahera, Tidore | Unid. ascidian |
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× | |||
Indonesia, Bali, Tulamben beach |
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Indonesia, SW Sulawesi, Spermonde Archipelago |
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× | ||||
Indonesia, NE Sulawesi, Bitung |
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Maldives, S Malé Atoll |
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× | ||||
Maldives, Faafu Atoll, Magoodhoo Island |
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Maldives, Faafu Atoll, Magoodhoo Island |
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Indonesia, W Halmahera, Ternate | × | |||||
Indonesia, Halmahera mainland, Tanjung Ratemu | Unid. ascidian |
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Indonesia, NE Sulawesi, Bitung |
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Indonesia, NE Sulawesi, Bitung |
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Indonesia, NE Sulawesi, Bitung |
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Indonesia, SW Sulawesi, Spermonde Archipelago | Unid. ascidian | × | ||||
Seychelles, E of Mahé | Unid. stolidobranch ascidian * | × | ||||
Indonesia, Bali, Sanur |
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Indonesia, Halmahera, Tidore | Unid. ascidian |
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Indonesia, Borneo, Sabah |
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Indonesia, Ambon, E coast | × | |||||
Panama, Playa Venao |
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Cape Verde Islands, S coast of São Vicente |
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Cape verde Island, São Nicocau |
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Indonesia, Bali, Tulamben area |
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Indonesia, Borneo, Sabah |
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* The host of
Data matrix of morphological characters used for phylogenetic analysis. Ordered characters in bold face, other characters unordered.
Species | |||||||||||||
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Outgroup species | |||||||||||||
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1 | 0 | 1 | 1 | 2 | 2 | 2 | 0 | 2 | 2 | 2 | 0 | 2 |
2 | 0 | 0 | 0 | 1 | 2 | 2 | 2 | 2 | 1 | 1 | 2 | 1 | |
3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | |
4 | 1 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 2 | 1 | 2 | 2 | |
5 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | |
6 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | |
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0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 1 | |
8 | 0 | 0 | 2 | 1 | 0 | 2 | 1 | 0 | 0 | 0 | 2 | 1 | |
9 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 2 | 0 | 0 | 0 | 0 | |
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1 | 0 | 0 | 0 | 1 | 1 | 2 | 1 | 1 | 0 | 1 | 2 | |
11 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 1 | |
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0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 2 | |
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0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 2 | |
14 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | |
15 | 2 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | |
16 | 1 | 0 | 0 | 2 | 2 | 2 | 2 | 2 | 0 | 2 | 2 | 2 | |
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1 | 0 | 0 | 0 | 1 | 1 | 2 | 2 | 0 | 1 | 0 | 0 | |
18 | 0 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | |
19 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 1 | 1 | |
20 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | |
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0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 1 | 0 | 0 | |
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0 | 1 | 1 | 0 | 2 | 1 | 1 | 1 | 1 | ? | 1 | 1 | |
23 | 1 | 0 | 0 | ? | 1 | 1 | 1 | 1 | 1 | 1 | ? | 2 | |
24 | 0 | 0 | 0 | 1 | ? | 1 | 1 | 1 | 1 | 0 | 2 | 2 |
Mitochondrial
Host records for
(modified from
The type species:
Known from shallow coastal waters of the Indo-West Pacific.
Associated with
Rostrum as long as antennular peduncle, with distoventral tooth. Pterygostomial angle produced. Basal segment of antennular peduncle with distolateral tooth minute, medioventral tooth strong, acute. Distolateral tooth of scaphocerite robust, 0.3 length of lamina. Dactylus of ambulatory pereiopods with flexor margin of corpus with few (usually 3) short teeth but without accessory tooth; unguis without terminal scales. Telson with two pairs of medium sized (approx. 0.17 of telson length) submarginal dorsal spines at 0.20 and 0.54 of telson length.
Body (Figs
Abdomen smooth, sixth segment 1.4 times longer than fifth, 1.4 times wider than long, posterolateral angle blunt, slightly produced, posteroventral angle blunt, not produced; pleura of first five segments broadly rounded.
Telson (Fig.
Eyestalk short, broader than long, slightly broader than diameter of hemispherical cornea.
Antennula (Fig.
Antenna (Fig.
Epistome with rather sharp anterior carina; labrum normal.
Paragnath well developed, alae with broad transverse more or less rectangular distal lobes, and small rounded more or less triangular ventromedial lobes; corpus very short, with shallow median excavation, bordered laterally by non-setose, small, oblique, carinae.
Second thoracic sternite (Fig.
Third thoracic sternite with indistinct shallow lateral carinae.
Fourth thoracic sternite with shallowly developed, medially notched plate formed by the lateral carinae.
Fifth thoracic sternite with well-developed lateral plates with medial broadened deep slit, posteromedial to second pereiopod coxae.
Sixth to eight thoracic sternites unarmed, broadening posteriorly.
Mandible (Fig.
Maxillula (Fig.
Maxilla (Fig.
First maxilliped (Fig.
Second maxilliped (Fig.
Third maxilliped (Fig.
First pereiopod (Fig.
Second pereiopods (Fig.
Ambulatory pereiopods short, stout. Dactylus of third pereiopod (Fig.
First pleopod of female (Fig.
Endopod of second pleopod (Fig.
Number of eggs approximately 11.
This is a small sized species. The maximum PoCL is 1.55 mm in adult females, 1.30 mm in adult males. The minimal PoCL in ovigerous females is 1.50 mm.
(Fig.
Specimens were found inside a colonial ascidian of the genus
Only known from the type locality.
The species is named
The species resembles
Thus far this is the only species of
Abdomen smooth, sixth segment 1.3 times longer than fifth, 1.4 times wider than long, posterolateral angle blunt, slightly produced, posteroventral angle blunt, not produced; pleura of first five segments broadly rounded.
Telson (Fig.
Eyestalk short, about as long as broad, as broad as diameter of hemispherical cornea.
Antennula (Fig.
Antenna (Fig.
Epistome anteriorly broadly rounded; labrum normal, oval.
Paragnath well developed, alae with broad transverse more or less rectangular distal lobes, and small rounded more or less triangular ventromesial lobes; corpus very short, with shallow median excavation, bordered laterally by non-setose, small, oblique, carinae.
Second thoracic sternite with anterior margin broadly rounded; without median process forming round tubercle.
Third thoracic sternite with indistinct shallow lateral carinae.
Fourth thoracic sternite with developed, bluntly triangular medial plate without median notch.
Fifth thoracic sternite with well-developed lateral plates with medial broadened deep slit, posteromedial to second pereiopod coxae.
Sixth to eight thoracic sternites unarmed, broadening posteriorly.
Mandible (Fig.
Maxillula (Fig.
Maxilla (Fig.
First maxilliped (Fig.
Second maxilliped (Fig.
Third maxilliped (Fig.
First pereiopod (Fig.
Second pereiopods (Fig.
Ambulatory pereiopods short, stout. Dactylus of third pereiopod (Figs
First pleopod with endopod almost half as long as exopod, with plumose setae laterally and distally, with long simple setae distomedially.
Uropods, with short unarmed protopodite; exopod broad, 2.2 times longer than central width, lateral margin feebly convex, without distolateral tooth, with minute spinule distolaterally; endopod exceeding exopod, about as long as telson, 2.8 times longer than wide.
Ovigerous female with about 100 eggs of 0.05 mm in diameter.
(Fig.
Colour patterns.
Solitary ascidian (A. Gittenberger Asc. 67).
Only known from its type locality at Tidore, Indonesia.
The species is named “
The species bears resemblance to
The morphological phylogenetic analysis (Fig.
The resulting tree from the incomplete
The resulting tree of the incomplete
Most
Both molecular and morphological phylogenetic analyses show good resolution in the distal part of the tree while basal support is low. The sister position of the species pair
The similar
SEM photos dactylus third pereiopod.
SEM photos unguis of third pereiopod.
SEM photos details unguis.
Several
Most
Phylogenetic analysis based on morphological dataset (Table
Phylogenetic analysis based on the
Phylogenetic analysis based on the
1 | Dactylus of ambulatory pereiopods without proximal teeth on flexor margin or with row of few shallow, forward directed teeth; unguis glabrous |
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– | Dactylus of ambulatory pereiopods with single large forward directed proximal tooth on flexor margin; distodorsal scales on unguis (except in |
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2 | Dactylus of ambulatory pereiopods with row of few shallow, forward directed teeth on flexor margin |
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– | Dactylus of ambulatory pereiopods with flexor margin entire |
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3 | Rostrum with distal ventral tooth; distolateral tooth of antennular basal segment slightly exceeding distal margin of segment |
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– | Rostrum without distal ventral tooth; distolateral tooth of antennular basal segment reaching distal margin of intermediate segment |
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4 | Unguis of dactylus of ambulatory pereiopods without or with few distal scales (not more than 5); small denticles between accessory and proximalmost tooth |
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– | Unguis of dactylus of ambulatory pereiopods with patch with many distal scales; no denticles between accessory and proximalmost tooth |
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5 | Rostrum not overreaching antennular peduncle |
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– | Rostrum overreaching antennular peduncle |
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6 | Telson with 2 pairs of dorsal spines; unguis without scales; propodi of ambulatory pereiopods with many long simple setae |
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– | Telson with 5 pairs of dorsal spines; unguis with few distodorsal scales; propodi of ambulatory pereiopods almost devoid of setae |
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7 | Unguis of dactylus of ambulatory pereiopods with two distal scales, and one denticle between accessory and proximalmost tooth |
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– | Unguis of dactylus of ambulatory pereiopods with one distal scale, and (with or without) five small denticles between accessory and proximalmost tooth |
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The authors would like to thank Bastian T. Reijnen for his assistance with the SEM, Bertie-Joan van Heuven for her help preparing and coating the pereiopods for the SEM, and Livia Oliveira for her help with the ascidian phylogeny.
1. Ventral teeth: 0, absent; 1, one subdistal; 2, one apical. Character states 0 and 1 are found in the outgroups. An apical tooth (often accompanied by some distal setae) is found in most
Variety in rostrum morphology and anterolateral angle variety in three
2. Length of rostrum: 0, falling short of antennular peduncle; 1, around the same length as antennular peduncle; 2, overreaching antennular peduncle. A small rostrum is found in all outgroups, while in most
3. Relative size rostrum to post-orbital carapace length: 0, around 0.15 to 0.45 times the PoCL; 1, around 0.75 times the PoCL. All outgroup species, as well as most
4. Relative size rostrum to hemispherical diameter of cornea: 0, around 4.0 times the cornea size; 1, around 2.5 to 3.0 times the cornea size; 2, around 2.0 times the cornea size. A rostrum-cornea ratio of 4.0 is found in the outgroup species
5. Anterolateral angle: 0, absent; 1, present. No angle is found in the outgroup species, as well as in
6. Ventromedial tooth basal segment: 0, small; 1, strongly developed; A strongly developed tooth is found in almost all
Variety in antennular peduncle. Note the well-developed ventromedial tooth in
7. Dimensions of intermediate segment: 0, about as long as wide or slightly broader than long; 1, about twice as long as wide. Most
8. Plumose setae on median margin of intermediate segment: 0, two or more setae; 1, one setae; 2, no setae. The specific setae are absent in
9. Maxilla: 0, upper lacinia and lower lacinia both well developed; 1, upper lacinia well-developed, lower reduced; 2, both lacinia almost completely fused.
10. First maxilliped; amount of distal setae on exopod: 0, eight or more setae; 1, five or six setae; 2, four setae. This character is treated as ordered; it is believed that the number of setae decreases in the exopods of
11. Second maxilliped; angle in median margin of basis: 0, absent; 1, distinct angle. Character state 1 is found in two outgroup species, except for
12. Second maxilliped; amount of distal setae on exopod: 0, eight or more setae; 1, five or six setae; 2, four setae. This character is treated as ordered (see character 10).
13. Third maxilliped; amount of distal setae on exopod: 0, eight or more setae; 1, five or six setae; 2, four setae. This character is treated as ordered (see character 10).
14. First pereiopod; ratio merus/carpus: 0, merus as long as carpus; 1, carpus shorter than merus. Character state 1 is present in outgroup species
15. Third pereiopod; dactylus; teeth on flexor margin: 0, teeth absent; 1, dactylus with simple teeth; 2, dactylus with minutely spinulate blunt tubercles. Character state 2 is only found in
Variety in dactylar morphology of all currently known
16. Third pereiopod; dactylus; teeth on flexor margin: 0, teeth absent; 1, teeth similar, increasing in size; 2, proximalmost tooth strong, large, directed forward. The teeth of
17. Third pereiopod; dactylus, unguis: 0, distal scales absent; 1, unguis with fewer than five distal scales; 2, unguis with more than five distal scales. Scales are absent in the two
18. Third pereiopod; dactylus; dimensions of corpus: 0, more than 2.0 times as long as broad; 1, less than 2.0 times as long as broad.
19. Third pereiopod; dactylus; accessory tooth: 0, present; 1, absent. Most
20. Third pereiopod; dactylus; additional forward-pointing teeth distal from proximalmost tooth: 0, absent; 1, two additional forward-pointing teeth. Only
21. Third pereiopod; dactylus; denticles between accessory and proximalmost tooth: 0, absent; 1, one, two or five denticles in flexor margin.
22. Position of distal pair of dorsal spines over telson length: 0, at about 1/2; 1, at about 2/3; 2, in distal 1/4. Character state 0 is present in
23. Maximum PoCL of male specimens: 0, PoCL longer than 5.5 mm; 1, PoCL between 5.5 and 2.0 mm; 2, between 2.0 and 0.5 mm. Depending on the availability of the specimens a “?” may be given to missing character states.
24. Maximum length of female specimens: 0, PoCL longer than 5.5 mm; 1, between 5.5 and 2.0 mm; 2, between 2.0 and 0.5 mm. Depending on the availability of the specimens a “?” may be given to missing character states.