Notograptus (Gill & Mooi, 1993)

Mooi, Randall D. & Gill, Anthony C., 2004, Notograptidae, sister to Acanthoplesiops Regan (Teleostei: Plesiopidae: Acanthoclininae), with comments on biogeography, diet and morphological convergence with Congrogadinae (Teleostei: Pseudochromidae), Zoological Journal of the Linnean Society 141 (2), pp. 179-205 : 197-201

BIOLOGY OF NOTOGRAPTUS

The largest specimen examined was 178 mm SL, although a 185 mm SL specimen was reported by Taylor (1964). Gill & Mooi (1993: 342, fig. 14a, b) described the eggs of Notograptus : 29–35 roughly cruciform chorionic projections arranged in a narrow ring closer to one pole of the egg than the other, 1–3 rows of projections wide. The projections are raised above the surface by a short pedicel, and the projection’s arms are produced into filaments, two to three greatly elongate. In other acanthoclinines, similar-looking eggs bind together via the filaments and the egg mass is guarded by the male in a burrow; similar behaviour is expected in Notograptus . In the specimen with largest ovarian eggs (USNM 173798, 170 mm SL), the eggs come in three basic size classes: very small (0.5– 0.6 mm in diameter), small (0.9–1.2 mm in diameter) and large (2.5–3.4 mm in diameter). This size distribution is indicative of a cyclical breeding cycle, perhaps lunar. Gravid females ranged in size from 88 mm SL to 170 mm SL and were found in collections made in February, April, May, June and September. Because our sample is small and collections were restricted to January through September, reproduction taking place in other months cannot be precluded. The largest specimens carried the most eggs (170 mm SL, 63 right ovary + 53 left ovary = 116 mature eggs; 170 mm SL, 47 + 42 = 89; 152 mm SL, 41 + 38 = 79; 103 mm SL, 24 total; 88 mm SL, 18 + 14 = 32). Note that the right ovary always contained more eggs than the left. Males do not have a modified intromittent organ, and eggs are likely fertilized after laying.

We have examined 99 specimens of Notograptus and found 32 with identifiable gut contents ( Table 2). Eighteen of these contained whole alpheid shrimp, always swallowed tail first ( Fig. 11A, B ). Thirteen (usually smaller) specimens contained only one or two claws, suggesting that smaller individuals are only able to obtain these parts. However, a 51 mm fish engulfed a whole 23 mm shrimp (claw tips to telson tip) that filled the entire gut from the anus to well into the buccal chamber ( Fig. 11C ). The largest individual examined (USNM 173797, 178 mm SL) had eaten a 24 mm SL gobiid. This apparent exception to a strict alpheid diet is likely an artefact of collection methods; rotenone collecting kills smaller fishes first that are often eaten by as yet unaffected bigger individuals that may not be piscivores under normal circumstances. Considering that the gobiid was in excellent condition in the gut (scales still intact, no digestion), and that the specimen was collected with ‘barbasco root’ (J. T. Williams, pers. comm.; a source of rotenone), opportunistic feeding is a likely explanation for this anomalous food item. Our observations strongly indicate that Notograptus are alpheid shrimp specialists.

Many morphological features of Notograptus appear to be adapted to accommodate their feeding speciality. The elongate body would permit entry into shrimp burrows. The extremely large gape, knobbly teeth and reduced gill arches would all facilitate eating large prey whole. The gut is straight, lacking the complicated intestinal bends that would hamper ingestion of large prey. Additionally, pleated skin around the anus (reminiscent of a baleen whale throat) allows evacuation of large indigestible items ( Fig. 12A ). In Alpheids

Species whole (w), Stomatopods (s) UnID Undigested N: size range parts (p) or shrimps (h) Amphi/Isopods Crust. Digested fish fish

Other

UnID Empty (*incidental) Notograptus 18w, 13p – – 2 – 1 (gobiid

99: 44–178 with scales) Acanthoclinus fuscus – – – 11 – 2 (1 with 3

68: 28–220 tripterygiids) A. littoreus – – – 4 – –

7: 56–119

A. marilynae – – – 1 – –

2: 90–95

A. matti – – – – – –

1: 52

Acanthoplesiops echinatus 1p – – – – –

1: 21

A. hiatti – – – 6 – –

9: 15–20

A. indicus 1p – – 1 – –

4: 19–27

Acanthoplesiops naka – – – – – –

1: 9.9

A. psilogaster – – – – – –

4: 12–22

Beliops xanthokrossos – – – – – –

1: 26

Belonepterygion fasciolatum - – – – – – –

43: 12–42

Anisochromis kenyae 2? 1 s – 9 – –

46: 13.8–25.6

A. mascarenensis – 1 h – 6 – –

11: 13.3–25.5

A. straussi – 3 s,2 h 1i 15 – –

82: 16.1–28.3

Blennodesmus scapularis 2p 2 s,2 h 2a 10 – –

120: 28.5–87

Congrogadus hierichthys 1p 1 h 1 5 1 –

30: 50–159

–

5

–

–

–

–

–

–

–

–

–

–

2

–

11

24

4

65

48

2

–

1

–

3

2

1

4

1

43

28

3

46

78

17

–

1 snail,

1 limpet

1 mollusc

1 snail

–

–

–

–

–

–

–

–

3 ostracods 1 crab

1 ostracods

3 gastropods 1 ostracod 1* mollusc

– Congrogadus malayanus – –

12: 31–70

C. spinifer 1w 3 s,2 h 33: 36–121

C. subducens 4w 1 s,1 h 75: 31–340

C. winterbottomi – 5 h

31: 66.1–119

Halidesmus polytretus – –

2: 57–57.3

H. scapularis – –

20: 46–98

H. socotraensis – –

6: 39.6–69.5

H. thomaseni – –

78: 29–134

Halimuraena hexagonata – –

28: 22–60

H. shakai 1p 1 s,11 h 57: 22–55

Halimuraenoides isostigma 1w? –

18: 65–278

Haliophis aethiopus – 1h

2: 49–50

H. guttatus 1w 2 s,6 h 308: 21–132

Natalichthys leptus – –

2: 52–56

N. ori – –

2: 54–60.5

N. sam – –

2: 40–43

Rusichthys explicitus – –

3: 40–52

R. plesiomorphus – –

1: 40

– 3 – –

– 10 – –

– 10 28 (a few of 2 these with undigested fish,

but often mixed with digested;

3 with Crustacea;

8 with 2–3 fish)

12a 2 – –

– 2 – –

– 20 (some – – might be shrimps)

– 4 – –

– 12 – –

8 9 – –

2 11 1 –

– 4 – –

– 1 – –

24 105 2 6

– – – –

– – – –

– – – –

– – – –

– – – – 8

2

29

3

–

–

–

40

–

17

8

–

30

–

–

–

–

– 1

15

–

8

–

–

2

26

11

13

5

–

132

2

2

1

3

1

–

3* small snails

–

1 mollusc

–

–

–

–

–

–

–

–

2* sponge spicules

–

–

1 pycnogonid? –

–

A comparison, Plesiops and Belonepterygion have recognizable stomachs with sharp bends, and Acanthoclinus has a bend apparently confined to a shorter portion of the posterior intestine in some species but substantially convoluted with two loops in A. fuscus . Beliops xanthokrossos has a straight gut with a substantial constriction that demarcates a short posterior intestine. Acanthoplesiops examined have a straight gut, which would serve as an additional synapomorphy with Notograptus . Pleated skin around the anus is found to a lesser degree in Acanthoclinus ( Fig. 12B ), and Acanthoplesiops has only slight anterior pleating. Such pleating does not occur in other acanthoclinines, Plesiops [ P. nigricans (Rüppell) , MPM 31314], Steeneichthys ( S. nativitatus Allen, MPM SOL 98–32; S. plesiopsus Allen & Randall, WAM P 30629.016) or other percoids [e.g. Cephalopholis cyanostigma (Valenciennes) , MPM 31524; Perca flavescens (Mitchill) , MPM 20093]. A reviewer pointed out what appears to be anal pleating in at least some Ecsenius ( Springer, 1988: figs 22, 23), but this pleating is of very limited extent being only about 6% of head length compared with 30 + % of head length in Notograptus .

Diet of acanthoclinines other than Notograptus has been difficult to determine, as the guts of most specimens examined were empty (105 specimens of 141) ( Table 2). Only Acanthoclinus and Acanthoplesiops had specimens with identifiable gut contents. Most Acanthoclinus contained unidentified crustaceans (16); remaining specimens contained various molluscs (four) and fishes (two). All of the few Acanthoplesiops with gut contents contained crustaceans (nine), with two of these having parts of alpheid shrimps. A further outgroup, the genus Plesiops , feeds mostly on small crustaceans, or parts of larger ones, and gastropods (64% crustaceans, 32% gastropods, 2% fishes, 1% pelecypods, 1% ophiuroid arms of 322 specimens with identifiable gut contents; 451 specimens had empty guts). In Plesiops , at least 20% of the gastropod shells contained hermit crabs, although most did not; some had opercula intact, and one gut contained an abalone, indicating that gastropods are a true portion of the diet. Overall, data are limited for plesiopids, but it appears that an alpheid diet is a specialization among derived acanthoclinines and is likely an autapomorphy of Notograptus .

A

Figures

Figure 11. X-radiographs of Notograptus sp., MPM 32586, showing whole alpheid shrimps in their guts. A, 73 mm SL, scale bar = 10 mm. B, Close-up of A, scale bar = 5 mm. C, 51 mm SL, scale bar = 5 mm, note claws of shrimp extend into buccal cavity.

Figure 12. Pleated anal region of A, Notograptus sp., USNM 173797, 148 mm SL; B, Acanthoclinus fuscus, MPM 32616, 190 mm SL; C, Congrogadus subducens, MPM 32613, 340 mm SL. Anterior to left. Note that pleated region in the Notograptus specimen is as large as the others’ despite being the smallest individual illustrated. Abbreviations: gp, genital papilla; a, anus; p, pleating; sr, first anal-fin element, spine in (A) and (B), ray in (C). Scale bar = 4 mm.