Endeis straughani Clark, 1970

Wang, Jianjia, Sun, Dong, Tian, Peng, Huang, Dinyong, Niu, Wentao & Zhang, Feng, 2021, A small collection of Endeis juveniles (Arthropoda: Pycnogonida: Endeidae) sorted from the fouling organisms on the R / V Dayangyihao, Biodiversity Data Journal 9, pp. 62343-62343 : 62343

Endeis straughani Clark, 1970

Phoxichilus charybdaeus (?). Haswell 1884: 1033.

Endeis straughani Clark 1970: 13-15, figs. 1-5; Krapp 1975: 86 (list); Staples 1982: 461-462 (literature), figs. 5K-M, Pl. 1 figs. A-B; Bamber and Costa 2009: 168 (list), 179 (text).

Endeis picta Bamber 1979: 251-254, figs. 1 A-I.

Phoxichilus charybdaeus (?). Haswell 1884: 1033.

Endeis straughani Clark 1970: 13-15, figs. 1-5; Krapp 1975: 86 (list); Staples 1982: 461-462 (literature), figs. 5K-M, Pl. 1 figs. A-B; Bamber and Costa 2009: 168 (list), 179 (text).

Endeis picta Bamber 1979: 251-254, figs. 1 A-I.

Materials

Type status: Other material. Occurrence : individualID: TIO2014DY34-5.001; individualCount: 1; lifeStage: juvenile; Taxon : scientificName: Endeis straughani Clark , 1970; kingdom: Animalia ; phylum: Arthropoda ; class: Pycnogonida ; order: Pantopoda ; family: Endeidae ; genus: Endeis ; Location : locationID: Mauritius; verbatimCoordinates: 71.5E; verbatimLatitude: 30.3S; Identification : identifiedBy: Jianjia Wang ; Event: year: 2015; month: 5; day: 7; habitat: amongst hydroids Type status: Other material. Occurrence : individualID: TIO2014DY34-5.002; individualCount: 1; lifeStage: juvenile; Taxon : scientificName: Endeis straughani Clark , 1970; kingdom: Animalia ; phylum: Arthropoda ; class: Pycnogonida ; order: Pantopoda ; family: Endeidae ; genus: Endeis ; Location : locationID: Mauritius; verbatimCoordinates: 71.5E; verbatimLatitude: 30.3S; Identification : identifiedBy: Jianjia Wang ; Event: year: 2015; month: 5; day: 7; habitat: amongst hydroids Type status: Other material. Occurrence : individualID: TIO2014DY34-5.003; individualCount: 1; lifeStage: juvenile; Taxon : scientificName: Endeis straughani Clark , 1970; kingdom: Animalia ; phylum: Arthropoda ; class: Pycnogonida ; order: Pantopoda ; family: Endeidae ; genus: Endeis ; Location : locationID: Mauritius; verbatimCoordinates: 80.4E; verbatimLatitude: 22.3S; Identification : identifiedBy: Jianjia Wang ; Event: year: 2015; month: 5; day: 12; habitat: amongst hydroids Type status: Other material. Occurrence : individualID: TIO2014DY34-5.004; individualCount: 1; lifeStage: juvenile; Taxon : scientificName: Endeis straughani Clark , 1970; kingdom: Animalia ; phylum: Arthropoda ; class: Pycnogonida ; order: Pantopoda ; family: Endeidae ; Location : locationID: Mauritius; verbatimCoordinates: 80.4E; verbatimLatitude: 22.3S; Identification : identifiedBy: Jianjia Wang ; Event: year: 2015; month: 5; day: 12; habitat: amongst hydroids Type status: Other material. Occurrence : individualID: TIO2014DY34-5.005; individualCount: 1; lifeStage: juvenile; Taxon : scientificName: Endeis straughani Clark , 1970; kingdom: Animalia ; phylum: Arthropoda ; class: Pycnogonida ; order: Pantopoda ; family: Endeidae ; genus: Endeis ; Location : locationID: Mauritius; verbatimCoordinates: 80.4E; verbatimLatitude: 22.3S; Identification : identifiedBy: Jianjia Wang; Event: year: 2015; month: 5; day: 12; habitat: amongst hydroids

Notes

Identification

TIO2014DY34-5.001. Trunk glabrous, completely segmented. Collar with flat protuberances laterally. Cephalon with two short spines distally. Lateral processes separated by slightly more than their own diameter, each with 1-3 short distal dorsal spines. Ocular tubercle taller than its base diameter, with pointed peak; two pairs of eyes pigmented distinctly. Abdomen pointing slightly backwards, almost as high as ocular tubercle, with two lateral spines distally (Fig. 1 C, D).

Proboscis barrel-shaped, leaning downwards at about 45 degrees, little longer than half of the trunk, slightly inflated at proximal third, with few short setae along the length and dense short setae around the mouth (Fig. 1 C, D).

Legs slender (Fig. 1 E). First coxa short, second coxa 2 times as long as first or third coxa, with some short setae ventrally. The main articles with setae sparsely dorsally and laterally; femur slightly longer than first tibia, each with one long seta located on the distal tubercle; second tibia longest, with one long setae distally. Tarsus small, subtriangular, with one spine and few setae ventrally. Propodus gently curved, with some short setae dorsally and three long setae distally; heel prominent, with 2-3 robust spines of increasing length distally, with one obliquely short spine (Fig. 1 F, G); sole with 4-6 spines and some slender setae. Main claw stout, half the length of propodus; auxiliary claws slender, almost half of main claw.

Measurements of TIO2014DY34-5.001 in mm: trunk length from the anterior margin of the cephalon to the tip of 4th lateral processes 1.34; width across second lateral processes 0.68; proboscis length 0.76; abdomen length 0.25. First leg: coxa-1 0.17, coxa-2 0.34, coxa-3 0.18, femur 0.98, tibia-1 0.84, tibia-2 1.04, tarsus 0.06, propodus 0.51, main claw 0.25, auxiliary claw 0.12.

Trunk length (TL) and Trunk Width (TW) of other specimens: TIO2014DY34-5.002 (TL 1.29; TW 0.75), TIO2014DY34-5.003 (TL 1.03; TW 0.58), TIO2014DY34-5.004 (TL 0.99; TW 0.57), TIO2014DY34-5.005 (TL 0.41; TW 0.33).

Distribution

The type location for E. straughani is Queensland, Australia ( Clark 1970). Bamber (1979) described E. picta from the coast of Ghana, West Africa which has since been synonymised with E. straughani by Staples (1982), thus greatly expanding the previous known range for this species. Our specimens were inadvertently collected from the fouling community on the expedition ship’s hull which probably originated from Port Louis, Mauritius, where the ship had previously been docked, expanding the species range even further.

Remarks

Identifying the juvenile Endeis specimens was not an easy task, especially since there were no adult males collected, which would have provided information on ovigers and cement glands that are very important for determining species in this genus. Our juvenile specimens agreed generally with the descriptions given by Clark (1970), Bamber (1979) and Staples (1982) and were especially consistent with the sub-adult characteristics mentioned by Staples (1982, p. 462). In addition, lateral process intervals, along with neck and lateral process spines and the variable number of heel spines in a single specimen, a characteristic also present on the adults described in Staples (1982) and which has not been reported for other Endeis species, added confirmation that these specimens were E. straughani or a very close relative.

Almost nothing is known about the Endeis life cycle, other than an incomplete description of the life cycle of Endeis spinosa (Montagu, 1808) by Dogiel (1913, Taf. XIX, figs. 1-4 and 7-8), who described the protonymphon larva and several developmental stages in this species. According to the four distinct types of pycnogonid postembryonic development which were characterised by Bain (2003), our Endeis specimens probably have the encysted larva type of development, even though we did not examine the hydroids in order to look for the earlier encysted stages.

Three specimens (TIO2014DY34-5.002, TIO2014DY34-5.003 and TIO2014DY34-5.004) have oviger buds (Fig. 1 H) and show variations in the length of trunk (range from 0.99 mm to 1.29 mm) and transparency of the cuticle. Of the specimens with oviger buds, which will become adult males, the oldest juvenile (TIO2014DY34-5.002) is larger than the other two individuals and is no longer quite as transparent (Fig. 1 B). The largest specimen (TIO2014DY34-5.001) is probably 1 or 2 moults away from the adult stage (Fig. 1 C-G).

In the absence of a complete life cycle to compare these specimens and based on the presence of four pairs of legs (4th pair still not completely developed) and also the presence of oviger buds in several of the specimens, they are probably at least 1 or 2 moults away from becoming adults ( Dogiel 1913, Bain 2003, Lovely 2005).

Endeis straughani can be distinguished from other similar Endeis species in the same region ( Stock 1965, Stock 1974) as follows: E. clipeata ( Möbius, 1902) has an apical cylindrical process on the propodus; E. meridionalis ( Böhm, 1879) has distorted femurs and E. mollis (Carpenter, 1904) has widely separated lateral processes and no spurs on the main leg segments. Staples (1982) pointed out the characteristics for distinguishing E. straughani from E. biseriata Stock, 1968 which has widely separated lateral processes (nearly three times the diameter of a single lateral process).

Stock (1970) recorded two Endeis species, Endeis pauciporosa Stock, 1970 and Endeis flaccida Calman, 1923 from the Gulf of Aqaba and E. flaccida also occurred in the Aden Habour ( Stock 1968). Endeis pauciporosa and E. flaccida can be easily distinguished from E. straughani since they have distorted femurs and alimentary diverticula in the legs with numerous branched caeca, respectively.

Endeis viridis Pushkin, 1976, found in the Crozet Archipelago and Kerguelen Islands ( Pushkin 1976, Pushkin 1993), can be distinguished from E. straughani by having distinctly slender legs and relatively long auxiliary claws, more than half the length of the main claw.

The specimens sustained some damage, such as unnaturally distorted tibiae and other kinds of damage during collecting, probably due to the pumping actions of the collecting apparatus (Fig. 1 A, B and E).

Clark’s specimens ( Clark 1970) retained a bright green colour after being preserved in alcohol and our specimens showed a range from bright purple to nearly transparent after being in alcohol for some time.

Figures

Figure 1. Endeis straughani, (TIO 2014 DY 34 - 5.003): A. trunk, dorsal view. (TIO 2014 DY 34 - 5.002): B. trunk, ventral view. (TIO 2014 DY 34 - 5.001): C. trunk, dorsal view; D. trunk, lateral view; E. leg 1; F. tarsus, propodus and claws of leg 1, enlarged, the arrow points to the obliquely short heel spine; G. tarsus, propodus and claws of leg 2, enlarged, the arrow points to the obliquely short heel spine. (TIO 2014 DY 34 - 5.002): H. cephalon, ventral view, the arrow points to the oviger bud. Scale bars A and B = 1 mm; C, D and E = 0.5 mm; F, G and H = 0.2 mm.