Principle results

 

Society islands

Berland (1934a) described knowledge of the spider fauna of Tahiti as follows:

“In spite of its universal prestige, especially in literary work, the fauna of this archipelago is badly known from the point of view which we are considering. In all, there are approximately 15 known species, of which the list is as follows: Pholcus ancoralis, Cyrtophora viridipes, Araneus theisi, Heteropoda regia, Corinna cetrata, Thorellia ensifera, Plexipps paykulli, Bavia aericeps, Athamus whitmeei, Mollica microphthalma and pusilla, Hasarius albocircumdatus, Ascyultus pterygodes, Lauharilla insulana. It is obviously very little: there is almost no trace of endemism; being given what one knows of archipelagoes close to the islands of the Societies, being also given that the species above are clearly Polynesian (excluding cosmopolitans, of course), one can conclude that Tahiti has not been sufficiently explored. It is not possible to currently affirm a real poverty of fauna, and we should await other investigations. What is significant above all, it is that the island fits well in the Polynesian group.”

This statement is a reasonable reflection of the knowledge of the spider fauna of the Society Islands prior to our expedition this summer (Marples 1957).

 

I. Tetragnatha

Species Diversity

 

Prior to this expedition, the only species of Tetragnatha reported from the Society islands were T. macilenta, T. huahinensis, T. maxillosa, and T. mandibulata. The only reported endemic was T. huahinensis. I have now collected on Tahiti, Moorea, and Raiatea. I have also examined historical collections at the Museum National Histoire Naturelle in Paris, and the Bishop Museum in Honolulu. Studies on historical collections have now shown that (1) Reports of the cosmotropical species T. mandibulata in Tahiti are probably not valid; these were misidentifications for either T. macilenta or T. nitens. (2) T. huahinensis is a synonym for T. macilenta. Studies of my own collections have revealed 4 new species of Tetragnatha, all of which are undescribed and appear to be endemic to middle and high elevations of the Society islands (from each of Tahiti and Moorea). In total, there are 7 species of Tetragnatha in the Society Islands: In addition to the 4 endemic species there is one possibly indigenous (T. macilenta), and two probably introduced (T. nitens and T. maxillosa).

 

Species Descriptions

 

T. sp. 1A. Tahiti, New Species:

Location	Elevation	Date	# specimens	Museum	Collector
Tahiti: Vallee Vaipuarii	600m	28Aug1928	1 male	Bishop	Adamson

This species was given then name T. mandibulata by Berland (1934a). Of this animal, Berland (1934a) says “L. Koch has given this name [Tetragnatha mandibulata], very badly defined by the description of Walckenaer [referring to Walckenaer 1841], to a Polynesian spider, which appears quite widespread in Oceania, since it is also known from Fiji, Samoa, Tonga, and Tahiti. For the examples that I have under the eyes, the teeth of the chelicerae accord well with the descriptions of Walckenaer (1841), but there are some variations in the color, my specimens having on the cephalothorax a brown median longitudinal band, and on the abdomen two series of spots in longitudinal lines, which recall the drawing of T macilenta L Koch, of Samoa”. This species is certainly similar to T. macilenta, but has a different tip to the conductor of the pedipalp. Recognition of this animal as a distinct species will warrant further morphological analyses.

 

T. sp. 2A. Tahiti, New Species:

Location	Elevation	Date	# specimens	Museum	Collector
Tahiti: Belvedere	580m	19Nov1999	2M,2F,1I	-	Gillespie
Tahiti Iti: Mt.Teatara	650m	7Jul2000	2M2f,12I	-	Gillespie

 

This species has been found in two locations, Tahiti Iti, 650m, and Tahiti Belvedere, 580m. This species appears to be distributed at middle elevations (580m at Belvedere – 650m on Tahiti Iti) throughout Tahiti. It has a “furry” appearance because of the thick hairs on its legs. The illustrations below show the chelicera (jaw) (left), pedipalp (middle) and conductor tip of the pedipalp (right) for a male of this species.

 

T. sp. 3A. Tahiti, New Species:

Location	Elevation	Date	# specimens	Museum	Collector
Tahiti: Mt Aorai	1700m	Nnov1999	2M,6F,6I	-	Gillespie
Tahiti: Mt Marau	1280m	6Jul2000	8F,2I	-	Gillespie
Tahiti: Mt Marau	1240m	6Jul2000	2M,1F	-	M.Arnedo

These are large, robust and colorful species with smooth legs (not furry) that occur at upper elevations (above 600m) on both Mt. Aorai and Mt. Marau. They frequently do not build webs, and are found at night, especially on Mt Aorai, foraging actively at night in the open. They are less common on Mt. Marau. The illustrations below show the chelicera (jaw) (left), pedipalp (middle) and conductor tip of the pedipalp (right) for a male of this species.

 

T. sp. 4A. Moorea, New Species:

Location	Elevation	Date	# specimens	Museum	Collector
Moorea: Paopao-Vaiare	320m	19Jun2000	1I	-	Gillespie
Moorea: Paopao-Vaiare	540m	3Jul2000	1F,2I	-	M.Arnedo
Moorea: 3 Coconuts	320m	18Jun2000	2I	-	Gillespie
Moorea: 3 Coconuts	320m	5Jul2000	2M,1F,1I	-	M.Arnedo

As in the low elevation species on Tahiti, this species, which is only on Moorea, has a “hairy” appearance. It is similar in gross morphology to the low elevation Tahiti species, but its chelicera and male pedipalp are very distinct (see diagram).

 

 

T. sp 5A Raiatea ( originally called T. laqueata) L.Koch

Location	Elevation	Date	# specimens	Museum	Collector
Raiatea: Opoa		1955?	1F	Bishop*	N. Krauss

Types: T. laqueata was first described by L. Koch from Upolu, Samoa. The type specimen was deposited in the Museum Godeffroy, which was absorbed into the Hamburg collection in Germany. I have examined 1 male and 3 females from the Hamburg Museum. These specimens are T. laqueata. However, since that time, T. laqueata has been reported in Raiatea by Marples (1957) based on a single female specimen (now in the Bishop Museum). I have now examined this specimen. It is not T. laqueata. It is most similar to T. insulicola Okuma, described from Lord Howe Island, but the genitalia is quite different.

            T. laqueata has also been recorded from the Bonin Islands and elsewhere in the north pacific. These records are incorrect: The specimens described by Okuma (1980) and Yaginuma (1979) are not T. laqueata.

 

T. macilenta L.Koch

Location	Elevation	Date	# specimens	Museum	Collector
Tahiti: Vaipaarii	600m	28Aug1928	1M,1I	Bishop*	Samson
Raiatea: Temehani	700m	3Sep1977	-	Bishop	WCGagne
Tahiti: Mt Marau	790m	6Jul2000	1I	-	Roderick
Tahiti: Mt Marau	820m	6Jul2000	1M,3I	-	Roderick
Tahiti: Mt Marau	1240m	6Jul2000	1M,1F,7I	-	Gillespie
Tahiti: Mt Aorai	1700m	Nov1999	1M,3I	-	Gillespie
Moorea: Trail to 3 Coconuts	320m	18Jun2000	1M,4F,1I	-	Gillespie
Moorea: Trail to 3 Coconuts	120m	21Jun2000	1M,2F,1I	-	Roderick
Moorea: Mouaputa	450m	11Ju12000	4F,4I	-	Roderick
BoraBora		Jul2000		-	M.Arnedo

* labeled T. mandibulata by Berland

Types: T. macilenta was first described by L. Koch from Upolu, Samoa. The type specimen was supposed to have been deposited in the Museum Godeffroy, which was absorbed into the Hamburg collection in Germany. However, 2 females only remain at the Hamburg Museum. These females do appear to be T. macilenta, and are from Upolu, Samoa. However, there is an additional male and female in the Hamburg collection (labeled “?syntype, T. macilenta”) from New South Wales, Australia. These latter specimens are T. valida. In the British Museum, London, T. macilenta L. Koch is represented by 1 male from the Solomon Islands (Rennell); 1 male from the Cook Islands, Aitutaki; 1 male and 1 female in forest, Upolu; and many specimens from Apia, Upolu, Samoa (most collected by Marples). However, I have not studied the British Museum collection in any detail. But the Type (male) is not at the British Museum; its location (if it exists at all) is currently unknown.

T. macilenta appears to be a very widespread species throughout Polynesia. Berland (1942) described a new species, T. huahinensis from Huahine. However, I have examined the type species (at Bishop Museum); this appears to be T. macilenta. Berland describes T. huahinensis as follows: Female (no male) color light brown, the margin and two stripes darker, labium brown, sternum light testaceous, the margin gray; abdomen gray with little silver plates on the sides and, in the posterior half, 2 rows of 4 small brown spots. Eyes, the two rows recurved, the first a little more, eyes nearly equal, the anterior lateral a little smaller, the lateral of the two rows a little farther from each other than the median. Chelae with a strong protruberance near the claw. Abdomen long, about 10x as long as wide. Total length 12mm. Society Islands, Huahine, Mt. Turi, alt.600-700ft, Oct. 1 1934, one female holotype. Berland goes on to say “I think that T. huahinensis is well characterized by the length of the abdomen and by the peculiar form of the chelae.” Interestingly, Berland drew a very similar diagram (Berland 1929) when describing T. macilenta L. Koch from Upolu, Samoa.

Chrysanthus (1975) cites Rower (1942), who cites Koch (1872) and Berland (1929). Neither mention Norfolk Is., Hawaii, or the Marquesas. Bonnet says that it is found in Samoa, Norfolk and the Marquesas, citing Berland, Rainbow, and Koch. None of the references mention Hawaii. Also, Berland's assignation of T. macilenta was somewhat loose. I found many specimens and discussions of T. macilenta from the Marquesas in the literature, but none of these match the actual description of T. macilenta. Okuma (1987) states that T. macilenta is found from Australia, New Guinea, Solomon Is., Norfolk Is., Samoa, Marianas, Tonga, Marquesas and Hawaii. However, the specimens she examined were all from Australia, New Guinea, Solomons, Tonga, New Britain, and Admiralty Islands. She did not examine any Polynesian species. I therefore conclude that T. macilenta has not been found further east than the Society Islands.

 

T. maxillosa Thorell 1895

Location	Elevation	Date	# specimens	Museum	Collector
Tahiti: Nr Tiupi Bay, Papaari	∞	3May1934	1M,1F	Bishop*
Tahiti: Papeete	-	-	1M,2F	Bishop*¶
Tahiti: Tiarei	-	-	-	Bishop*¶
Tahiti: Vallée de la Reine	460ft	17Dec1928	1M,1F	Bishop*¶
Raiatea: Utoroa	-	-	-	Bishop*
Raiatea: Temehani Pl.	1400ft	5oct1934	-	Bishop	EC Zimmerman
Raiatea: Opoa.	-	-	1I	Bishop	-
Tahiti: Papenoo Valley	195m	7Jul2000	3M,2F,1I	-	Gillespie
Moorea: Trail to 3 Coconuts	220m,over stream	18Jun2000	-	-	Gillespie
Raiatea: Temehani Pl.	800m,over stream	12Jul2000	2M,3F,1I	-	Gillespie

∞ Sweeping grasses and low herbage; * det. C. Okuma

T. maxillosa was first described by Thorell (1895). There is a good deal of confusion because Thorell (1895) first described the species based on a specimen of T. mandibulata that he had misidentified in 1890. Thorell also describes the T. mandibulata that Koch (1872) referred to as T. kochi. Berland uses the name T. mandibulata "Koch, not Walckenaer". However, in almost all cases, he appears to mean T. maxillosa. Much of Berland's material has now been examined by C. Okuma. In most cases, Berland's identifications of T. mandibulata appear to be T. maxillosa:

 

T. nitens (Audouin in Savigny). Ua Pou and Nuku Hiva:

Location	Elevation	Date	# specimens	Museum	Collector
Moorea: Baie de Cook	0m	Mar1955	1F	Bishop	Krauss
Moorea: Gump Field Station	0m	18Nov1999	8M,10F,1I	-	Gillespie

This species is found along the coast of Moorea.

 

T. Mandibulata Walckenaer (no confirmed records in french Polynesia):

This species was described by Walckenaer (1841) as follows:

Mandibles carried in front, very-prominent, very-elongate, reinflated in their medium, divergent and whose stem is finished by a spine or hook* of a red blade. Cylindrical abdomen, lengthened, narrower than the corselet, a little bent or raised in the posterior part, color green obscure. The corselet is lengthened, rougeatre, is bordered of a line yellow fine. The palpi and the legs are red. There are grayish or white hairs on the corselet, the legs, and the mandibles.

From the Marainnes, Guam.

* believed to refer to the first stout dent of the ventral row, which extends directly forward beside the base of the fang (Chrysanthus 1975).

The confusion is that Berland uses the drawing of Koch (which looks very like T. maxillosa, but apparently Thorell, 1895, calls this species T. kochi Note: need to check on Thorell 1895 Descriptive Catalogue of the Spiders of Burma: 1-406, London) to identify species. Okuma has now been through much of the material and correctly identified many of the Berland labels of T. mandibulata as T. maxillosa.

There has been a good deal of confusion regarding T. mandibulata, as Chrysanthus (1975) notes. In particular:

T. mandibulata Keyserling, 1865 = T. keyserlingi Simon 1890 (p.134) (Note: look up Simon, E. 1890. Études arachnologiques, 22e meoires. Ann Soc. Ent. Fr (6) 10: 131-136.

T. mandibulata L. Koch = T. kochi Thorell 1895 (p.140)

T. mandibulata Thorell 1890 = T. maxillosa Thorell 1895 (p.139) It is said that this species is known from Norfolk Is, Hawaii, and Marquesas (Chrysanthus 1975).