Parathelges aniculi ( Whitelegge, 1897 )

Williams, Jason D. & Boyko, Christopher B., 2015, Abdominal bopyrid parasites (Crustacea: Isopoda: Bopyridae: Athelginae) of diogenid hermit crabs from the western Pacific, with descriptions of a new genus and four new species, Raffles Bulletin of Zoology 64, pp. 33-69 : 49-57

Parathelges aniculi ( Whitelegge, 1897)

(Figs. 8–12)

Athelges aniculi Whitelegge, 1897: 149–151 , pl. 7, figs. 5a-c; Springthorpe & Lowry, 1994: 37.

Parathelges aniculi, Bonnier, 1900: 380 (list); Shiino, 1950: 164 (list); Codreanu, 1961: 137 (list); Markham, 1972: 58 (list), 76 (key); Markham, 2010: 153 (list), 179–183, figs. 28–31 (synonymy); An et al., 2011: 2906 (mention).

Parathelges weberi Nierstrasz & Brender à Brandis, 1923: 105, pl. 7, figs. 28a-d; Nierstrasz & Brender à Brandis, 1929: 302, figs. 10, 11; Nierstrasz & Brender à Brandis, 1931: 201 (list); Shiino, 1950: 164 (list); Codreanu, 1961: 137 (list); Ball & Haig, 1972: 100; Markham, 1972: 58 (list), 76 (key); Haig & Ball, 1988: 160; An et al, 2011: 2906 (mention).

Parathelges whiteleggei Nierstrasz & Brender à Brandis, 1931: 200, 201, pl. 1, fig. 4, text fig. 92; Shiino, 1950: 164 (list); Codreanu, 1961: 137 (list); Markham, 1972: 58 (list), 76 (key); An et al., 2011: 2906 (mention).

Athelges “undescribed species” Haig & Ball, 1988: 161.

Parathelges “? whiteleggei ” Haig & Ball, 1988: 173.

Material examined. With Male Form A: Indonesia: Mature lectotype female (9.5 mm) and mature paralectotype male (4.7 mm) ( ZMUC CRU- 8616) of Parathelges whiteleggei , infesting “ Pagurus sp. ” [= Dardanus hessii ] (5.9 mm SL; in vial with parasites), “Javasee” [Indonesia], coll. unknown, 4 December 1910; immature female (2.3 mm), mature male (1.4 mm) ( LACM CR19755901), infesting female Pseudopaguristes monoporus (1.8 mm SL), inhabiting unknown shell, Indonesia, Seram, Stn. 2, around Pulau Marsegu (03°00’S, 128°02.5’E), coll. E. Ball et al., 31 March–1 April 1975. Philippines: Mature female (9.7 mm), mature male (3.1 mm on SEM stub) ( USNM 1283380), infesting male Calcinus gaimardii (4.7 mm SL), inhabiting shell of Drupella cornus (Röding) , Cebu, Olango Island and Sulpa Islet, coll. JDW, 9 July 1997; mature female (10.2 mm), mature male (2.9 mm) (pers. coll.), infesting male Calcinus latens (4.2 mm SL), inhabiting shell of D. cornus , Oriental Mindoro, Puerto Galera, Coco Beach, coll. JDW, 12 January 1999; mature female (7.75 mm), mature male (1.77 mm on SEM stub) ( USNM 1283381), infesting intersex Calcinus minutus (3.6 mm SL), inhabiting shell of D. cornus , Oriental Mindoro, Puerto Galera, Coco Beach, coll. JDW, 14 January 1999; mature female (6.0 mm), mature male (3.0 mm) ( ZRC 2015.0502), infesting female C. latens (3.0 mm SL), inhabiting unidentified shell, Cebu, Olango Island and Sulpa Islet, coll. JDW, 9 July 1997; mature female (7.4 mm), mature male (3.6 mm) ( USNM 1283382), infesting female C. latens (3.3 mm SL), inhabiting unidentified shell, Oriental Mindoro, Puerto Galera, La Laguna Beach, coll. JDW, 31 July 1997; mature female (7.71 mm on SEM stub), mature male (2.8 mm on SEM stub) ( USNM 1283383), infesting male C. minutus (3.1 mm SL), inhabiting unidentified shell, Oriental Mindoro, Puerto Galera, La Laguna Beach, coll. JDW, 18 June 2000; mature female (16.1 mm), mature male (3.0 mm) ( ZRC 2015.0503), infesting female C. gaimardii (4.0 mm SL), inhabiting unidentified shell, Oriental Mindoro, Puerto Galera, La Laguna Beach, coll. JDW, 18 June 2000. Australia: Mature female (13.4 mm), mature male (2.9 mm) ( MV J62873 ), infesting unknown host, inhabiting shell of Phasianella ventricosa (fide label), Cape Wickham, King Island, Tasmania, 39°35’S 143°57’E, coll. Marine Research Group of Victoria, 9 March 1980; juvenile female (3.9 mm) ( MV J62879 ), infesting Areopaguristes tuberculosus (fide label), inhabiting unknown shell, eastern Bass Strait, Victoria, 39°51’11”S 148°38’32”E, 51 m depth, coll. Marine Research Group of Victoria, 28 September 1980; 2 mature females (8.2, 12.2 mm), juvenile female (6.5 mm), 2 males (1.8, 3.2 mm) ( MV J62881 ), infesting unknown hosts, inhabiting unknown shells, Victoria, coll. unknown; 8 mature females (7.5-11.1 mm), 5 juvenile females (3.0–6.0 mm), mature male (3.0 mm) ( MV J62882 ), infesting unknown host, inhabiting unknown shells, Flinders, Victoria, 29°S 145°02’E, coll. S. W. Fulton & F. E. Grant, 31 December 1900; mature female (9.8 mm) ( MV J62895 ), infesting A. tuberculosus (fide label), inhabiting unknown shell, 5.31 nautical miles off Barracoota [oil rig], 8 nm off shore, 16.14 nm off Snapper, Victoria, 23 fms (= 42.1 m), coll. N. Coleman, early November 1987; 2 mature females (12.2, 16.2 mm), mature male (3.6 mm) ( MV J62872 ), infesting Paguristes sulcatus (fide label), inhabiting P. ventricosa (fide label), Naracoopa, King Island, Tasmania, 39°55’11”S 144°07’35”E, coll. Marine Research Group of Victoria, 8 March 1980; mature female (10.4 mm), mature male (3.3 mm) ( MV J62868 ), infesting female P. sulcatus (8.2 mm SL), inhabiting unknown shell, Shoreham, Westernport Bay, Victoria, 38°25’S 145°03E, coll. J. A. Kershaw, 30 March 1902. Taiwan: Mature female (10.2 mm), mature male (3.0 mm) ( USNM 1283405), infesting female Calcinus vachoni (3.5 mm SL), inhabiting unknown shell, Haikou, Pingtung, coll. R. Yoshida, 30 June 2011; mature female (9.0 mm), mature male (2.7 mm) ( USNM 1283406), infesting male C. vachoni (3.6 mm SL), inhabiting unknown shell, Chuanfanshih, Pingtung, coll. R. Yoshida, 27 July 2011; mature female (10.1 mm), mature male (2.9 mm) ( USNM 1283407), infesting female C. vachoni (3.5 mm SL), inhabiting unknown shell, Aimen Beach, Penghu, coll. R. Yoshida, 4 August 2011; mature female (8.5 mm), mature male (2.2 mm) ( USNM 1283407), infesting female C. vachoni (3.2 mm SL), inhabiting unknown shell, Aimen Beach, Penghu, coll. R. Yoshida, 4 August 2011.

With Male Form B: Indonesia: Mature female (2.4 mm), mature male (2.0 mm) ( LACM CR19755891), infesting male Calcinus laevimanus , inhabiting unknown shell, Indonesia, Banda Islands, Stn. 5b, north side Banda Besar, south side of Selat Lontor (04°32.2’S, 129°53’E), coll. E. Ball et al., 7 April 1975. Philippines: Mature female (5.5 mm) with female Cabirops sp. , immature male (1.2 mm) ( USNM 1283384), infesting intersex C. latens (2.7 mm SL), inhabiting shell of D. cornus , Batangas, Sombrero Island, coll. JDW, 5 July 1997; mature female (8.4 mm) with epicaridium larvae, mature male (2.5 mm) ( ZRC 2015.0504), infesting female Diogenes sp. (3.4 mm SL), inhabiting shell of Strombus sp. , Cebu, Mactan Island, Maribago, coll. JDW, 7 July 1997; mature female (6.5 mm), mature male (2.8 mm) ( ZRC 2015.0505), infesting female C. minutus (3.3 mm SL), inhabiting unidentified shell, Oriental Mindoro, Puerto Galera, La Laguna Beach, coll. JDW, 31 July 1997; immature female (2.9 mm on SEM stub), mature male (1.8 mm on SEM stub), cryptoniscus (0.6 mm on SEM stub) ( USNM 1283385), infesting female C. gaimardii (3.1 mm SL), inhabiting shell of Tenguella granulata (Duclos) , Batangas, Sombrero Island, coll. JDW, 31 July 1997; mature female (7.2 mm), mature male (2.5 mm) ( USNM 1283386), infesting female C. minutus (4.4 mm SL), inhabiting shell of Latirolagena smaragdulus (Linnaeus) , Oriental Mindoro, Puerto Galera, La Laguna Beach, coll. JDW, 31 July 1997; mature female (7.3 mm), mature male (2.7 mm) ( USNM 1283387), infesting intersex C. latens (2.3 mm SL), inhabiting shell of Tenguella granulata , Oriental Mindoro, Puerto Galera, Coco Beach, coll. JDW, 12 January 1999; mature female (7.0 mm), mature male (2.4 mm) ( USNM 1283388), infesting male C. latens (3.6 mm SL), inhabiting shell of Drupella rugosa (Born) , Oriental Mindoro, Puerto Galera, Coco Beach, coll. JDW, 12 January 1999; mature female (9.9 mm), mature male (3.0 mm on SEM stub, pers. coll.) ( USNM 1283389), infesting female C. gaimardii (4.0 mm SL), inhabiting shell of D. rugosa, Puerto Galera, Coco Beach , coll. JDW, 14 January 1999; mature female (7.4 mm), mature male (2.8 mm) ( USNM 1283390), infesting male C. minutus (3.6 mm SL), inhabiting shell of D. rugosa , Oriental Mindoro, Puerto Galera, Coco Beach, coll. JDW, 15 April 1999; mature female (5.0 mm), mature male (2.2 mm) ( USNM 1283391), infesting intersex C. minutus (3.3 mm SL), inhabiting shell of Cypraea sp. , Bataan, Morong, coll. JDW, 25 April 1999; mature female (10.8 mm), mature male (3.9 mm) ( USNM 1283392), infesting female C. gaimardii (3.9 mm SL), inhabiting shell of D. cornus , Batangas, Anilao, coll. JDW, 13 February 1999; mature female (9.4 mm), mature male (2.7 mm) (pers. coll.), infesting male C. minutus (3.6 mm SL), inhabiting shell of D. cornus , Batangas, Anilao, coll. JDW, 13 February 1999; mature female (8.1 mm), mature male (2.9 mm) ( USNM 1283393), infesting intersex C. minutus (3.6 mm SL), inhabiting shell of D. rugosa , Batangas, Anilao, coll. JDW, 13 February 1999; mature female (10.7 mm), mature male (3.1 mm) ( USNM 1283394), infesting female C. latens (2.8 mm SL), inhabiting shell of Cypraea sp. , Bataan, Morong, coll. JDW, 28 February 1999; immature female (1.86 mm on SEM stub), mature male (1.1 mm) ( USNM 1283395), infesting female Calcinus pulcher (2.2 mm SL), inhabiting unidentified shell, Cebu, Mactan Island, Maribago, coll. JDW, 10 July 1997; mature female (8.1 mm), mature male (3.0 mm) ( USNM 1283396), infesting female C. minutus (3.8 mm SL), inhabiting unidentified shell, Oriental Mindoro, Puerto Galera, La Laguna Beach, coll. JDW, 28 July 1997; mature female (12.3 mm), mature male (3.3 mm) ( USNM 1283397), infesting female C. latens (2.1 mm SL), inhabiting unidentified shell, Bataan, Mabayo, coll. JDW, 21 February 1999; mature female (7.3mm), mature male (2.6 mm) ( USNM 1283398), infesting female C. minutus (3.6 mm SL), inhabiting unidentified shell, Oriental Mindoro, Puerto Galera, La Laguna Beach, coll. JDW, 27 March 1999; juvenile female (4.1 mm), mature male (2.02 mm) ( USNM 1283399), infesting male C. gaimardii (2.18 mm SL), inhabiting unidentified shell, Batangas, Sombrero Island, coll. JDW, 10 June 2000; juvenile female (2.1 mm), mature male (0.99 mm) ( USNM 1283400), infesting male C. minutus (2.4 mm SL), inhabiting unidentified shell, Batangas, Sombrero Island, coll. JDW, 10 June 2000.

Male Form Unknown: Tuvalu: Mature holotype female of Athelgue aniculi (9.1 mm) ( AM G-1423), infesting Aniculus typicus Dana, 1852 [= A. aniculus ] (host lost), inhabiting shell of Turbo setosus Gmelin (fide Whitelegge, 1897) [= T. (Marmarostoma) setosus ], Tuvalu, Funafuti [Ellice Islands, ca. 08°50’S, 177°10’E], coll. C. Hedley, between 21 May and 7 August 1896. Indonesia: Mature holotype female of Parathelges weberi (11.14 mm) ( ZMA), infesting unknown host (host lost), locality unknown, coll. unknown; mature female (5.0 mm) ( LACM CR19755893), infesting male “ Calcinus undescribed sp.” [= C. lineapropodus ], inhabiting unknown shell, Indonesia, Banda Islands, Stn. 19, outside of Gunungapi (04°30.3’S, 129°52.3’E), 0–12 m, coll. E. Ball, 28–30 April 1975. Philippines: Immature female (3.4 mm on SEM stub) ( USNM 1283401), infesting female C. latens (2.6 mm SL), inhabiting shell of Peristernia sp. , Batangas, Sombrero Island, coll. JDW, 5 July 1997; mature female (13.3 mm) ( USNM 1283402), infesting male C. gaimardii (4.4 mm SL), inhabiting unidentified shell, Cebu, Mactan Island, Maribago, coll. P. Cassidy, 29 December 1996; mature female (7.94 mm) ( USNM 1283403), infesting male C. latens (4.84 mm SL), inhabiting unidentified shell, Cebu, Mactan Island, Maribago, coll. P. Cassidy, 29 November 1996; mature female (3.9 mm) ( USNM 1283404), infesting female C. minutus (2.6 mm SL), inhabiting unidentified shell, Puerto Galera, Coco Beach, coll. JDW, 15 January 1999. Taiwan: Immature female (8.8 mm) ( USNM 1283409), infesting male Dardanus lagopodes (7.8 mm SL), inhabiting unknown shell, Huapinyan, Shaoliuchiu, coll. R. Yoshida, 29 July 2011; mature female (7.3 mm) ( USNM 1283410), infesting female C. vachoni (2.6 mm CL), inhabiting unknown shell, Fongguei, Penghu, coll. R. Yoshida, 4 August 2011. Redescription. Reference female (Fig. 8A). Body length 8.8 mm, maximal width 3.9 mm, head length 1.2 mm, head width 1.2 mm, pleon length 3.6 mm. Body longer than broad; pereon slightly to moderately (~30°) recurved. All body regions and pereomeres distinctly segmented (Figs. 8A, 10A).

Head length and breadth subequal with convex lateral margins, anterior margin flattened to slightly concave, posterior margin convex (Figs. 8A, 10A). Eyes lacking. Antennule of three articles, distal ends of last two articles with setae; antenna of five articles, all articles with scales, distal ends of last three articles with setae (Fig. 8B). Maxilliped (Figs. 8F, 10B) with elongate, ovate anterior lobe lacking palp; smaller, rounded posterior lobe bearing thin, short, acute spur. Barbula (Figs. 8G, 10B) with three short, smooth tapering lobes anterolaterally; one short, smooth tapering lobe present on subsequent pereomere (see Remarks).

Pereon of seven distinct pereomeres, broadest across pereomeres V, VI, tapering anteriorly and posteriorly. Pereomere I posterior margin overlapped by head, pereomere II posteriorly convex, pereomeres III, IV posteriorly straight, pereomeres V – VII posteriorly concave; pereomeres II – VII with posterolateral flaps near base of pereopods, most pronounced on pereomeres III – V. First oostegites extended over head (Figs. 8A, 10A). Oostegites completely enclosing brood pouch; posteriormost oostegite with fringe of setae on posterior margin. First oostegite anterior lobe laterally expanded and folded, posterior lobe slightly recurved and tapering to rounded point, internal ridge smooth (Figs. 8E, 10C). All pereopods subequal in size, bases slightly longer and thinner in posterior pairs (Fig. 8A). Pereopod I (Figs. 8C, 10A) anterior to head, pereopod II parallel to head, slightly longer gap between pereopods V, VI, pereopods VI, VII with ovate lobe on ischium (Fig. 8D).

Pleon with six distinct pleomeres. Pleomeres I– IV (Figs. 8A, 10A) with elongate-ovate biramous pleopods, arising from common thick peduncle, no lateral plates; pleomere V without appendages; pleotelson with uniramous, short, tapered, posterolaterally-directed uropods (Figs. 8A1–A3, 10A).

Reference Male Form A (Fig. 8H, I). Length 3.1 mm, maximum width 1.4 mm, head length 0.3 mm, head width 0.8 mm, pleon length 0.8 mm. Head subovate, widest medially, tapering posteriorly, fused with pereomere I. Eye pigmentation present at lateral junction of head and first pereomere, pronounced angled pair of cephalic slits either side of midline ( Fig. 9B ). Antennule of three articles (Figs. 8K, 9A, C), distalmost two articles distally setose, first and second articles covered in scales with filamentous extensions. Antenna (Figs. 8K, 9A, C) of five articles, extending posterolaterally from head, distalmost article with tuft of long setae, penultimate article with distal row of long setae, third article with ventrolateral subdistal row of short setae, second article with numerous short rows of scales with filamentous extensions, first article covered in scales with filamentous extensions.

Pereomeres IV, V broadest, tapering anteriorly and posteriorly. All pereomeres directed laterally with rounded lateral margins; pereomeres VI, VII with posterolateral small notch and setae (Fig. 8J). First two pairs of pereopods (Figs. 8K, 9D, E) with longer dactyli than posterior pairs (first and second subequal), dactyli strongly recurved and slightly twisted, touching base of propodus anterolateral to base of raised medial region on ventral surface of propodus. Dactyli of pereopods III (Figs. 8L, 9D) through VII (Figs. 8M, 9F) with broad, thin scales distally. Propodi of first and second pereopods much larger than other pairs, ventral surface with two to three medially offset rows of denticles distally reduced to one curved row proximally, short group of denticles and few short setae on opposite side forming pocket into which distal point of dactylus inserts. Carpi and meri of first and second pereopods ( Fig. 9A, D, E ) much shorter and stouter proportionally to other segments of other pereopods, all articles distinctly separated, distal margin of carpus with tuft of short setae and raised area of bladelike denticles, ventral surface of basis with scales with filamentous extensions.

Pleon (Figs. 8H, I) ovate with slightly expanded anterior portion, tapering posteriorly, all pleomeres fused with lateral indication of segmentation. No midventral tubercles, pleopods, or uropods (Fig. 8I).

Reference Male Form B ( USNM 1283393) (Fig. 10D). Length 2.9 mm, maximum width 1.1 mm, head length 0.2 mm, head width 0.7 mm, pleon length 0.8 mm. Head subovate, widest medially, tapering posteriorly, fused with pereomere I (Fig 10D). Irregular eye pigmentation present at lateral junction of head and first pereomere, pronounced angled pair of cephalic slits either side of midline. Antennule of three articles (Figs. 10E, 11A, B), distalmost two articles distally setose, first and second articles covered in scales with filamentous extensions. Antenna (Figs. 10E, 11A, B) of five articles, extending posterolaterally from head, distalmost article with tuft of long setae, penultimate article with distal row of long setae, third article with ventrolateral subdistal row of setae and few scales, second article with numerous short rows of scales with short filamentous extensions, first article covered in scales with short filamentous extensions.

Pereomeres IV, V broadest, tapering anteriorly and posteriorly. All pereomeres directed laterally with rounded lateral margins. First two pairs of pereopods (Figs. 10E, 11C, E) with slightly longer dactyli (first slightly longer than second) than posterior pairs (Figs. 10F, 11D, F), moderately recurved and inserting at base of medial raised region on ventral surface of propodus ( Fig. 11C ), otherwise subequal in size to other pereopods. Ventral surface of propodi with two to three medially offset rows of denticles distally reduced to one curved row proximally, short group of denticles and few short setae on opposite side forming pocket into which distal point of dactylus inserts. Carpi and meri of first and second pereopods of similar proportions to other segments as in other pereopods, all articles distinctly separated, distal margin of carpus with tuft of short setae and raised area of bladelike denticles, ventral surface of bases with scales with short filamentous extensions ( Fig. 11C ).

Pleon subtriangular, tapering posteriorly (Fig. 10D), all pleomeres fused without lateral indication of segmentation; posterior margin rounded. No midventral tubercles, pleopods, or uropods.

Cryptoniscus larva ( USNM 1283385) ( Fig. 12 ). Length 665 µm, maximum width 265 mm at pereomere 2; body teardrop shaped ( Fig. 12A ). Cuticular surface smooth, covered with numerous thin setae ( Fig. 12B, D ).

Head anterior margin concave, posterior margin concave, widest at posterolateral junction with pereomere 1 ( Fig. 12A ). Eyes lacking. Antennule of three articles ( Figs. 12C ), smooth, basal article approximately three times longer than broad, distomesial region with tuft of setae, article 2 proximolateral and distolateral regions each with a tuft of setae, article 3 with distal setae and aesthetascs ( Figs. 12C ). Antennae of eight articles (four peduncular and four flagellar) ( Fig. 12A, D ), articles 1–3 cylindrical, smooth ( Fig. 12D ); flagellar articles much narrower than peduncular articles, proximal three with a pair of terminal setae, distalmost article longest with distal tuft of elongate setae. Oral cone triangular, anteriorly directed ( Figs. 12A, C ).

Pereomere 1 broadest, tapering posteriorly. Body pigmentation lacking. Pereomeres with entire (not toothed) coxal plates 1–7 ( Fig. 12A ). Pereopods 1–7 isomorphic, dactyli entire (non-bifid), smooth, long and straight with ventral setal comb, stout seta 1/3 distance from base of dactylus ( Fig. 12E ); propodi with few cuticular ridges lined with very short setae ( Fig. 12E ); ventral surfaces of carpi and meri with few cuticular ridges, distoventral edge of merus with one long seta ( Fig. 12E ).

Pleon with 5 pleopods composed of basis (sympod), exopod, and endopod, all covered with short, thin setae ( Fig. 12A ). Endopods and exopods with plumose setae ( Fig. 12A ). Pleotelson quadrangular, endopods approximately twice as long as exopods, basis with 1 distolateral seta, endopods and exopods with terminal setae ( Fig. 12A ).

Type localities. Athelgue aniculi : Tuvalu, Funafuti ( Whitelegge, 1897); Parathelges weberi : “unbekannt” (Nierstrasz & Brender à Brandis, 1923); Parathelges whiteleggei : “Javasee” [ Indonesia] (Nierstrasz & Brender à Brandis, 1931).

Distribution. Tuvalu ( Whitelegge, 1897), “Netherländischen- Ostindien” (Nierstrasz & Brender à Brandis, 1929), Indonesia (Nierstrasz & Brender à Brandis, 1931, Form A; Haig & Ball, 1988, Form A, B), Papua New Guinea ( Ball & Haig, 1972, herein; Form A, herein), Australia: Queensland ( Markham, 2010), Victoria (Form A, herein), China: South Sea ( An et al., 2011), Philippines (Forms A, B, herein).

Hosts. Diogenidae : Areopaguristes tuberculosus ( Whitelegge, 1900) (herein, Form A), Aniculus aniculus ( Whitelegge, 1897) , Calcinus gaimardii (herein, Form A, B), Calcinus laevimanus ( Ball & Haig, 1972; Haig & Ball, 1988), Calcinus latens (herein, Forms A, B), Calcinus minutus (herein, Forms A, B), Clibanarius sp. , Dardanus hessii (Nierstrasz & Brender à Brandis, 1931; herein, Form A), Dardanus sp. ( Markham, 2010) , Paguristes sulcatus (herein, Form A), Pseudopaguristes monoporus ( Haig & Ball, 1988, Form A), Spiropagurus sp. ( An et al., 2011), Diogenes sp. (herein, Form B).

Size Range (Length). With Male Form A: Females: to 16.2 mm (herein), males: to 3.6 mm (herein); with Male Form B: Females: to 12.3 mm (herein), males: to 3.9 mm (herein).

Remarks. Markham (2010) included all records of Parathelges whiteleggei and P. weberi in synonymy with P. aniculi . We examined the type specimens of P. aniculi , P. whiteleggei and P. weberi and agree with this synonymy. However, although females are indistinguishable, there are two male morphotypes that we designate as Form A and Form B. Characters that distinguish P. aniculi Form A and Form B are: dactyli on pereopods 1 and 2 much more elongate and recurved compared to those of pereopods 3–7 (Form A; Fig. 9A ) vs. dactyli on pereopods 1 and 2 subequal in length and curvature similar to those of pereopods 3–7 (Form B; Fig. 11A ), antennae and pereopods with longer setae in Form A ( Fig. 9A ) than in Form B ( Fig. 11A ). The two male morphotypes are identified separately in the material examined in the present study; prior records require re-examination. Future molecular studies are needed to determine whether the two forms represent interspecific variation or cryptic species. Unfortunately, the holotype of Athelgue aniculi was not accompanied by a male. In addition, P. enoshimensis Shiino, 1950 may be a synonym of P. aniculi but re-examination of topotypic material is necessary.

The barbula was defined by Markham (1988) as the processes occurring on the posteroventral border of the head of a female bopyrid. Parathelges aniculi exhibits a barbula with three lobes ( Markham, 2010; herein); however, a fourth lobe similar in shape and appearance occurs posterolaterally to the barbula (see Figs. 8G, 10B) on what appears to be the second pereomere and as such is not part of the barbula proper. This structure does not appear to have been reported before and may be taxonomically informative. The lobes are easily overlooked unless the oostegites are fully lifted to expose the ventral side of the pereon.

Although Markham (2010) listed the type pair of Parathelges whiteleggei as “ holotype ” and “ allotype,” no such designation was made by Nierstrasz & Brender à Brandis (1931) and Markham’s (2010) mention of a “ holotype ” is not a valid lectotype designation (ICZN, 1999; Article 74.7). We herein designate the female type specimen of Parathelges whiteleggei (ZMUC CRU-8616) as the lectotype. Although we did not examine the specimens reported by Ball & Haig (1972) as P. weberi , it is likely that this is the correct identification. The specimens identified by Markham and reported by Haig & Ball (1988) as “an undescribed species of Athelges ” were examined and found to conform to P. aniculi (Form B). The pair of specimens reported by Ball & Haig (1988, as “ Parathelges ? whiteleggei ”) are confirmed to be P. aniculi (Form A). The type host of Parathelges whiteleggei was reported by Nierstrasz & Brender à Brandis (1931) and repeated by McDermott et al. (2010) as “ Pagurus sp. ” but is actually Dardanus hessi .

Parathelges aniculi most commonly parasitises hermit crabs in the genus Calcinus , although they are known from species in eight other genera ( McDermott et al., 2010; herein Table 2). One Calcinus minutus (USNM 1283393) with P. aniculi (Form B) contained a pseudionine bopyrid ( Bopyrissa sp. ) in the left branchial chamber. One female of P. aniculi (male Form B) from the Philippines contained a hyperparasitic isopod ( Cabirops sp. ) in the brood chamber.

Figures

Fig. 9. Parathelges aniculi (Whitelegge, 1897) Form A, scanning electron micrographs of male, USNM 1283383 (A–D), USNM 1283380 6-31-87 (E, F). A, ventral view of anterior end; B, dorsal view of head, showing cephalic slits (presumptive sensory structures, see Bourdon et al., 1981); C, left antennule, antenna, pereopods 1 and 2; D, left pereopods 2 and 3; E, right pereopod 2, detail of distal end of dactyl, propodus and carpus; F, right pereopod 7. Scale bars = 500 µm [A, B], 400 µm [C, F], 200 µm [D], 50 µm [E].

Fig. 11. Parathelges aniculi (Whitelegge, 1897) Form B, scanning electron micrographs of male, USNM 1283389 (A–D), USNM 1283385 (E, F). A, ventral view of anterior end; B, right antennule, antenna and pereopod 1; C, right antenna, pereopods 1 and 2, oblique view; D, right pereopods 2 and 3; E, right pereopod 2, detail of distal end of dactyl, propodus and carpus; F, left pereopod 7. Scale bars = 500 µm [A], 200 µm [B, C], 200 µm [D], 50 µm [E, F].

Fig. 12. Parathelges aniculi (Whitelegge, 1897) Form B, scanning electron micrographs of cryptoniscus larva, USNM 1283385 (A-F). A, ventral view; B, head, dorsal view; C, right antennule, ventral view; D, right antenna, laterodorsal view; E, right pereopods 1–4; F, right pereopods 5–7. Scale bars = 200 µm [A], 100 µm [B, D], 50 µm [C, E, F].